Add GRPC service in crAPI

[JBAhire]

Is your feature request related to a problem? Please describe. Currently, crAPI only supports REST endpoints. We can only identify and demo REST vulnerabilities with crAPI. We should add a GRPC service which will make it easier to demo GRPC vulnerabilities.

Describe the solution you'd like @piyushroshan, can you please add more context on a plausible solution here?

[dhruv-singhal-github]

@piyushroshan @mathew-jose for what features do we require grpc service?

[piyushroshan]

To showcase unsecured and unencrypted grpc channel. It would be best to convert the existing go service to grpc. This would showcase how API vulnerabilities are independent of framework used

[dhruv-singhal-github]

@JBAhire I can work on this.