Kubernetes configuration for Keep Maintainer bot (#3689)

In this PR we update the configuration of keep-client maintainer
deployment running in keep-test and keep-prd.

### Template
We define a template for running the keep-client in maintainer mode with
all the available modules:
- spv
- walletCoordination
- bitcoinDifficulty

### keep-prd

In keep-prd cluster we replaced the previously running Bitcoin
difficulty maintainer with a new instance of all-in-one maintainer bot.

### keep-test

In keep-test we have to adjust the setup to work correctly with the
`LightRelay` contract.

Bitcoin Relay used by the tTBTC system on testnet environment is an
optimized version of the Light Relay implemented by
[GoerliLightRelay](https://github.com/keep-network/tbtc-v2/blob/main/solidity/contracts/test/GoerliLightRelay.sol)
contract. The reason the Light Relay had to be modified for testnet is
that on Bitcoin testnet difficulty often drops to `1`, which makes the
blocks validation on such change impossible to the regular Light Relay
contract.

The `GoerliLightRelay` version doesn't require a maintainer bot to
submit block headers on difficulty change. It accepts ad-hoc difficulty
alignment according to the tests needs.

For these reasons, we are running two instances of keep-maintainer.

The first instance `keep-maintainer` is connected to Bitcoin testnet and
runs `spv` and `walletCoordination` modules.

The second instance `keep-maintainer-staging` is connected to Bitcoin
mainnet and runs only `bitcoinDifficulty` module.

The test environment setup for the relay contract is subject to change
in the coming weeks, so the configuration defined in this PR for the
keep-test is expected to be modified then.

Author: lukasz-zimnoch

infrastructure/kube/keep-prd/btc-difficulty/kustomization.yaml

@@ -0,0 +1,33 @@
+resources:
+  - ../../templates/keep-maintainer
+
+namespace: default
+
+commonLabels:
+  app: keep-maintainer
+  type: all
+  network: mainnet
+
+images:
+  - name: keep-maintainer
+    newName: gcr.io/keep-prd-210b/keep-client
+    newTag: v2.0.0-m4-rc
+
+configMapGenerator:
+  - name: keep-maintainer-config
+    behavior: merge
+    literals:
+      - network=mainnet
+      - electrum-api-url=ws://electrumx.bitcoin:8080
+    files:
+      - .secret/keep-maintainer-keyfile
+
+secretGenerator:
+  - name: keep-maintainer-eth-account-password
+    files:
+      - .secret/keep-maintainer-password
+
+generatorOptions:
+  disableNameSuffixHash: true
+  annotations:
+    note: generated

infrastructure/kube/keep-prd/btc-difficulty/maintainer-statefulset.yaml

@@ -0,0 +1,14 @@
+# Keep Maintainer Staging Mainnet
+
+Bitcoin Relay used by the tTBTC system on testnet environment is an optimized version
+of the Light Relay implemented by [GoerliLightRelay](https://github.com/keep-network/tbtc-v2/blob/main/solidity/contracts/test/GoerliLightRelay.sol)
+contract. The reason the Light Relay had to be modified for testnet is that on
+Bitcoin testnet difficulty often drops to `1`, which makes the blocks validation
+on such change impossible to the regular Light Relay contract.
+
+The `GoerliLightRelay` version doesn't require a maintainer bot to submit block
+headers on difficulty change. It accepts ad-hoc difficulty alignment according to
+the tests needs.
+
+The setup defined in this directory is meant for testing the bitcoin difficulty module 
+of the maintainer bot with the Bitcoin mainnet blockchain state.

infrastructure/kube/keep-prd/keep-maintainer/kustomization.yaml

@@ -0,0 +1,50 @@
+resources:
+  - ../../templates/keep-maintainer
+
+namespace: default
+
+# Regular testnet maintainer doesn't run bitcoinDifficulty module due to specifics
+# of LightRelay running on testnet (GoerliLightRelay). This setup is running
+# the `bitcoinDifficulty` module of maintainer connected to Bitcoin mainnet.
+nameSuffix: -staging
+
+commonLabels:
+  app: keep-maintainer-staging
+  type: bitcoinDifficulty
+  network: goerli
+
+images:
+  - name: keep-maintainer
+    newName: gcr.io/keep-test-f3e0/keep-client
+    newTag: latest
+
+configMapGenerator:
+  - name: keep-maintainer-config
+    behavior: merge
+    literals:
+      - network=testnet
+      - electrum-api-url=wss://electrumx-server.tbtc.network:8443
+    files:
+      - .secret/keep-maintainer-keyfile
+
+secretGenerator:
+  - name: keep-maintainer-eth-account-password
+    files:
+      - .secret/keep-maintainer-password
+
+patches:
+  - target:
+      kind: StatefulSet
+      name: keep-maintainer
+    patch: |-
+      - op: add
+        path: /spec/template/spec/containers/0/args/-
+        value: --bitcoinDifficulty
+      - op: replace
+        path: /spec/template/spec/containers/0/env/0/valueFrom/secretKeyRef/name
+        value: eth-network-goerli
+
+generatorOptions:
+  disableNameSuffixHash: true
+  annotations:
+    note: generated

infrastructure/kube/keep-test/btc-difficulty/kustomization.yaml

@@ -0,0 +1,54 @@
+resources:
+  - ../../templates/keep-maintainer
+
+namespace: default
+
+commonLabels:
+  app: keep-maintainer
+  # The current setup runs spv and walletCoordination modules as a workaround
+  # for reasons mentioned in `patches` property below.
+  type: all
+  network: goerli
+
+images:
+  - name: keep-maintainer
+    newName: gcr.io/keep-test-f3e0/keep-client
+    newTag: latest
+
+configMapGenerator:
+  - name: keep-maintainer-config
+    behavior: merge
+    literals:
+      - network=testnet
+      - electrum-api-url=ws://electrumx.bitcoin-testnet:8080
+    files:
+      - .secret/keep-maintainer-keyfile
+
+secretGenerator:
+  - name: keep-maintainer-eth-account-password
+    files:
+      - .secret/keep-maintainer-password
+
+patches:
+  # Testnet's maintainer shouldn't run `--bitcoinDifficulty` module, as the testnet
+  # uses modified version of LightRelay contract (GoerliLightRelay) that doesn't
+  # require the bitcoin difficulty to be submitted. This patch defines manually
+  # which modules should be started.
+  - target:
+      kind: StatefulSet
+      name: keep-maintainer
+    patch: |-
+      - op: add
+        path: /spec/template/spec/containers/0/args/-
+        value: --spv
+      - op: add
+        path: /spec/template/spec/containers/0/args/-
+        value: --walletCoordination
+      - op: replace
+        path: /spec/template/spec/containers/0/env/0/valueFrom/secretKeyRef/name
+        value: eth-network-goerli
+
+generatorOptions:
+  disableNameSuffixHash: true
+  annotations:
+    note: generated

infrastructure/kube/keep-test/btc-difficulty/maintainer-statefulset.yaml

@@ -0,0 +1,17 @@
+resources:
+  - maintainer-statefulset.yaml
+
+commonLabels:
+  app: keep-maintainer
+  type: all
+
+configMapGenerator:
+  - name: keep-maintainer-config
+    literals:
+      - log-level=info
+      - log-format=json
+
+generatorOptions:
+  disableNameSuffixHash: true
+  annotations:
+    note: generated