[AppGate] Implement the MVP AppGateServer

[red-0ne]

Summary

Human Summary

AppGateServer implementation that supports JSONRPC over HTTP. Used to sign and send RelayRequests, verify the corresponding RelayResponse's supplier signature and reply to the client with the original service response.

The appGateServer will build rings for the application and cache them in order to send relays to the network signed. This PR also implements signature verification for the RelayerProxy.

This PR adds the cobra cmd to start the AppGateServer from the CLI.

Outstanding TODOs:

• Move the rign creation and caching logic into a shared package
• Emit delegation events from the App module and listen for these to know when to invalidate a cached ring

AI Summary

Summary generated by Reviewpad on 10 Nov 23 22:45 UTC

This pull request introduces various changes to several files. Here is a summary of the changes:

1. root.go: Adds support for an appgate server command to the existing root command.

2. go.sum: Adds new dependencies to the project.

3. simple_signer.go: Adds the implementation of the SimpleSigner type, which provides functionality for signing messages using a keyring and key name.

4. appgateserver.go: Provides logic related to creating and managing rings for signing relays in the appgateserver package.

5. relay_verifier.go: Makes changes related to verifying relay request and response signatures.

6. endpoint_selector.go: Adds functionality for selecting a relayer endpoint based on service ID and JSON RPC type.

7. errors.go: Defines error variables registered using sdkerrors.Register for the appgateserver and relayer packages.

8. interface.go: Introduces the Signer interface, which abstracts the signing of a message.

9. options.go: Adds functions for setting signing information and listening URL for the appgate server.

10. session.go: Adds functionality for retrieving the current session for a given service in the appgateserver package.

11. relay.go: Adds methods for generating signable bytes for relay requests and responses.

12. proxy package: Adds functions related to creating and managing rings for signing relays in the proxy package.

13. options.go: Adds functions for setting signing information and listening URL for the appgate server.

14. session.go: Adds functionality for retrieving the current session for a given service in the appgateserver package.

15. relay.go: Adds methods for generating signable bytes for relay requests and responses.

16. errors.go: Makes changes to error variables in the relayer/proxy package.

17. go.mod: Adds new dependencies to the project.

18. pkg/client/block/client.go: Updates the block client functionality and error handling.

19. prog.go: Deletes the file containing code for generating a package using GoMock reflections.

20. proxy.go: Adds new import statements and additional fields related to the application module and ring caching.

21. appGateServer.go: Contains the implementation of the appGateServer struct, which handles listening to application requests, signing and relaying them, and verifying response signatures.

Please review these changes for your pull request.

Type of change

Select one or more:

• New feature, functionality or library
• Bug fix
• Code health or cleanup
• Documentation
• Other (specify)

Testing

• Run all unit tests: make go_develop_and_test
• Verify Localnet manually: See the instructions [here](TODO: add link to instructions)

Sanity Checklist

• I have tested my changes using the available tooling
• I have performed a self-review of my own code
• I have commented my code, updated documentation and left TODOs throughout the codebase

[h5law]

Left a few comments on adding some TODOs for me to pick up. But this is great work bringing over the MVP 10/10

[h5law]

@red-0ne @Olshansk I will be picking this up tmrw 20231107 and bringing it into main for the E2E relay and will address all the comments when I do <3 exciting times!!!!

[red-0ne]

@red-0ne @Olshansk I will be picking this up tmrw 20231107 and bringing it into main for the E2E relay and will address all the comments when I do <3 exciting times!!!!

I addressed most of the comments, but haven't touched the signature parts yet. As per @Olshansk comments signatures should go into Relay(Request/Reply) methods.

I am now making the changes

[Olshansk]

Just FYI that this is finally happening @noot :)

[h5law]

Big up @noot loving the ring library <3

[Olshansk]