Cleanup ERPC server codebase

[blockchainluffy]

Things to do:

• Implement use of runner in spawning a go routine
• Implement check for tx inclusion and if not included, retry it. This check should be done in same go routine, combining tx metrics inclusion time and retry mechanism
• Implement error returned gauge metrics as per above retry implementation
• Add config file for non sensitive values to be configured, rather than using environment variables for all configurations
• Update test coverage
• Update file names according to the naming conventions