[DataApi] Add Service Availability Handler

[siddimore]

Why are these changes needed?

Expose Service Availability for Disperser and Churner.

Synthetic Check

Once this change is deployed Synthetic check can be run as below:

Preprod deployment

Disperser

• Serving
  query: /v1/eigenda/service-availability?service-name=disperser
  Response:
  {ServiceName: "Disperser", ServiceStatus: "SERVING"} with status_code: 200
• Not Serving
  query: /v1/eigenda/service-availability?service-name=disperser
  Response:
  {ServiceName: "Disperser", ServiceStatus: "NOT_SERVING"} with status_code: 503

Churner

• Serving
  query: /v1/eigenda/service-availability?service-name=churner
  Response:
  {ServiceName: "Churner", ServiceStatus: "SERVING"} with status_code: 200
• Not Serving
  query: /v1/eigenda/service-availability?service-name=churner
  Response:
  {ServiceName: "Churner", ServiceStatus: "NOT_SERVING"} with status_code: 503

Both

• Serving
  query: /v1/eigenda/service-availability
  Response:
  [{ServiceName: "Disperser", ServiceStatus: "SERVING"}, {ServiceName: "Churner", ServiceStatus: "SERVING"}] with status_code: 200

Change

1. Implement endpoint for EigenDA public Service
2. Add Handler for getting Service Status
3. Create GRPC pool of connections for faster access
4. Check GRPC Health of Server by calling endpoints:
   // disperser-goerli.eigenda.eigenops.xyz,
   // churner-goerli.eigenda.eigenops.xyz

Checks

• I've made sure the lint is passing in this PR.
• I've made sure the tests are passing. Note that there might be a few flaky tests, in that case, please comment that they are not relevant.
• Testing Strategy
  • Unit tests
  • Integration tests
  • This PR is not tested :(