Add dev container that supports github codespaces development.

Author: RossBugginsNHS

.devcontainer/devcontainer.json

@@ -2,10 +2,9 @@
   "containerEnv": {
     "GITHUBMONITOR": "false",
     "MAKECONFIG": "true",
-    "SHOWWELCOME": "true",
+    "SHOWWELCOME": "false",
     "UPDATEFROMTEMPLATE": "false"
   },
-  "image": "ghcr.io/nhsdigital/nhs-notify-devcontainer-loaded:1.0.17",
-  "name": "Notify Loaded 1.0.17",
-  "postStartCommand": "mkdir -p ~/.gnupg && echo '## 1-day timeout' > ~/.gnupg/gpg-agent.conf && echo 'default-cache-ttl 86400' >> ~/.gnupg/gpg-agent.conf && echo 'max-cache-ttl 86400' >> ~/.gnupg/gpg-agent.conf && gpg-connect-agent reloadagent /bye 2>/dev/null || true"
+  "image": "ghcr.io/nhsdigital/nhs-notify-devcontainer-loaded-codespaces:1.0.19",
+  "name": "Digital Letters Codespaces"
 }

.devcontainer/local-dev/devcontainer.json

@@ -0,0 +1,11 @@
+{
+  "containerEnv": {
+    "GITHUBMONITOR": "false",
+    "MAKECONFIG": "true",
+    "SHOWWELCOME": "true",
+    "UPDATEFROMTEMPLATE": "false"
+  },
+  "image": "ghcr.io/nhsdigital/nhs-notify-devcontainer-loaded:1.0.19",
+  "name": "Digital Letters Local Dev",
+  "postStartCommand": "mkdir -p ~/.gnupg && echo '## 1-day timeout' > ~/.gnupg/gpg-agent.conf && echo 'default-cache-ttl 86400' >> ~/.gnupg/gpg-agent.conf && echo 'max-cache-ttl 86400' >> ~/.gnupg/gpg-agent.conf && gpg-connect-agent reloadagent /bye 2>/dev/null || true"
+}