refactor: create base Observer and Signer struct to group common data of EVM observer/signer and Bitcoin observer/signer

[ws4charlie]

Describe the Issue

• The EVM client and Bitcoin client structs have common data fields which can be grouped into a BaseClient struct. BaseClient can then be reused by EVM client, Bitcoin client and future chain clients (e.g., DogeClient) by exposing unified methods.
• The EVM signer and Bitcoin signer structs have common data fields which can be grouped into a BaseSigner struct. BaseSigner can then be reused by EVM client, Bitcoin client and future chain clients (e.g., DogeSigner) by exposing unified methods.
• The commonly used loggers can also form a BaseClientLog struct and be reused by future chain clients.

Expected Outcome

// BaseClientLog is the base logger for external chain client
type BaseClientLog struct {
	// Chain is the parent logger for the chain
	Chain zerolog.Logger

	// Inbound is the logger for incoming transactions
	Inbound zerolog.Logger

	// Outbound is the logger for outgoing transactions
	Outbound zerolog.Logger

	// GasPrice is the logger for gas prices
	GasPrice zerolog.Logger

	// Compliance is the logger for compliance checks
	Compliance zerolog.Logger
}

// BaseClient is the base client struct for external chain client
type BaseClient struct {
	// the external chain
	chain chains.Chain

	// the external chain's parameters
	chainParams observertypes.ChainParams

	// tss signer
	tss interfaces.TSSSigner

	// zetacore bridge
	bridge interfaces.ZetaCoreBridger

	// zetacore context
	coreContext *corecontext.ZetaCoreContext

	// the latest block height of external chain
	lastBlock uint64

	// the last successfully scanned block height
	lastBlockScanned uint64

	// lru cache for blocks
	blockCache *lru.Cache

	// client db for persistency
	db *gorm.DB

	// stop channel
	stop chan struct{}

	// telemetry server
	ts *metrics.TelemetryServer
}


// BaseSigner is the base signer struct for external chain signer
type BaseSigner struct {
	// the external chain
	chain chains.Chain

	tssSigner interfaces.TSSSigner

	// the loggers
	logger           zerolog.Logger
	loggerCompliance zerolog.Logger

	// zetacore context
	coreContext *corecontext.ZetaCoreContext

	// telemetry server
	ts *metrics.TelemetryServer
}

[lumtis]

Would Doge require a different signer implementation from Bitcoin?

[ws4charlie]

Would Doge require a different signer implementation from Bitcoin?

Yeah. It will be a separate/different implementation.