add Stellar support for mcms adapters, RPC providers, chain config, and blockchain

.changeset/rich-pumas-cheat.md

@@ -0,0 +1,5 @@
+---
+"chainlink-deployments-framework": patch
+---
+
+add a Stellar RPC provider and chain

chain/stellar/provider/rpc_provider.go

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+package provider
+
+import (
+	"context"
+	"errors"
+
+	"github.com/smartcontractkit/chainlink-deployments-framework/chain"
+	"github.com/smartcontractkit/chainlink-deployments-framework/chain/stellar"
+)
+
+type RPCChainProviderConfig struct {
+	NetworkPassphrase string
+	FriendbotURL      string
+	SorobanRPCURL     string
+}
+
+func (c RPCChainProviderConfig) validate() error {
+	if c.NetworkPassphrase == "" {
+		return errors.New("network passphrase is required")
+	}
+	if c.FriendbotURL == "" {
+		return errors.New("Friendbot URL is required")
+	}
+	if c.SorobanRPCURL == "" {
+		return errors.New("Soroban RPC URL is required")
+	}
+
+	return nil
+}
+
+type RPCChainProvider struct {
+	selector uint64
+	config   RPCChainProviderConfig
+
+	chain *stellar.Chain
+}
+
+var _ chain.Provider = (*RPCChainProvider)(nil)
+
+func NewRPCChainProvider(selector uint64, config RPCChainProviderConfig) *RPCChainProvider {
+	return &RPCChainProvider{
+		selector: selector,
+		config:   config,
+	}
+}
+
+func (p *RPCChainProvider) Initialize(_ context.Context) (chain.BlockChain, error) {
+	if p.chain != nil {
+		return p.chain, nil // already initialized
+	}
+
+	if err := p.config.validate(); err != nil {
+		return nil, err
+	}
+
+	p.chain = &stellar.Chain{
+		ChainMetadata: stellar.ChainMetadata{Selector: p.selector},
+	}
+
+	return *p.chain, nil
+}
+
+func (p *RPCChainProvider) Name() string {
+	return "Stellar RPC Chain Provider"
+}
+
+func (p *RPCChainProvider) ChainSelector() uint64 {
+	return p.selector
+}
+
+func (p *RPCChainProvider) BlockChain() chain.BlockChain {
+	if p.chain == nil {
+		return nil
+	}
+	return *p.chain
+}

chain/stellar/stellar_chain.go

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+package stellar
+
+import (
+	chaincommon "github.com/smartcontractkit/chainlink-deployments-framework/chain/internal/common"
+)
+
+type ChainMetadata = chaincommon.ChainMetadata
+
+// Chain represents a Stellar network instance used by the Chainlink Deployments Framework (CLDF).
+type Chain struct {
+	ChainMetadata
+}