Feature/token tap

[KyleSmith19091]

This PR introduces a new Token Tap Service for testing and ledger management, providing functionality to initialize token taps, list available tokens, and mint tokens on multiple blockchain networks.

Protobuf Definitions

• New Service: TokenTapService in proto/meshtrade/testing/ledger/token_tap/v1/service.proto
  • InitialiseTokenTaps (WRITE) - Initialize token taps
  • ListTokenTaps (READ) - List available tokens
  • MintToken (WRITE) - Mint tokens with blockchain-specific options
• New Options: proto/meshtrade/testing/ledger/token_tap/v1/option.proto
  • MintTokenOptions - Configurable mint options supporting Stellar and Solana networks
  • StellarMintOptions with memo support
  • SolanaMintOptions with token version selection (Legacy/2022)
• Role-Based Access Control: Added new roles in proto/meshtrade/iam/role/v1/role.proto
  • ROLE_LEDGER_TOKEN_TAP_ADMIN - Full token tap access
  • ROLE_LEDGER_TOKEN_TAP_VIEWER - Read-only token tap access