Allow to pass alias placeholders in JSON-RPC request

[nmvalera]

Summary

Allow to next arguments pass JSON-RPC to replace

• privateFor c.f. https://docs.google.com/document/d/1cgfbBb7EJ-CAvkR21k0h4GdEC_vS1XdMrEg-PIPvaak/edit#heading=h.hebsvnkcovnm
• privacyGroupId c.f. https://docs.google.com/document/d/1cgfbBb7EJ-CAvkR21k0h4GdEC_vS1XdMrEg-PIPvaak/edit#heading=h.njkpsii4nbvo

Acceptance Criteria

• Enable to parse alias placeholders in JSON-RPC request (the current proposal is {{...}})
• Allow eth_sendTransaction interceptor to use alias in privateFor
• Allow eth_sendTransaction interceptor to use alias in privacyGroupId argument #377
• Allow eth_sendTransaction interceptor to use alias in privateFrom #393
• Allow eth_sendRawPrivateTransaction interceptor to use alias in privateFor #388
• Allow eth_sendRawPrivateTransaction interceptor to use alias in privacyGroupId argument
• Allow eea_sendTransaction interceptor to use alias in privateFor
• Allow eea_sendTransaction interceptor to use alias in privacyGroupId (in this case if the alias value is a string it should be treated as the privacy group id, if alias value is a string array then it should be treated as an array to pass in privateFor
• Allow eea_sendTransaction interceptor to use alias in privateFrom
• E2E tests for all JSON-RPC methods

[dolanor]

Based on the discussion with @darioAnongba and @ggarri , I will make the alias value an interface that could handle string or array instead of just an array that could have 1 or many values.

[dolanor]

All the work on EEA has been merged with #421
There is one test missing in the E2E, it is the test of the PrivacyGroupID alias pointing to a PrivacyGroupID (as a string), as opposed as a PrivacyGroupID alias pointing to an array alias. It would be good to add it to ensure completeness.