E2E tests for beacon and node endpoints

[nidhi-singh02]

Correct implementations of handlers that exist but are wrong and add tests. For any not present in eth2client, skip for now.

• beacon / GetGenesis - GenesisForkVersion implemented test(node-api) : Beacon headers and genesis API  #2002 and Genesis Time implemented feat(node-api) : Implemented genesis time  #2014

• beacon / GetBlockHeaders - Not present in eth2client - resolved the error, tested via the swagger - working

  • handled the case when no input/request is passed
  • Allow query via parent root
  • Allow query when both params are provided

• beacon / GetBlockHeaderByID - Signature needs to be implemented - resolved the error

• node / Syncing - In progress - chore(node-endpoint): Implement node syncing #2100

• node / Version - working - chore(node-endpoint) : Implement node_version #2046

[imanpajand]

thanks

[nidhi-singh02]

#2002 and #2014

[nidhi-singh02]

#2046 - Node Version

[nidhi-singh02]

Node syncing - #2100 (WIP)