[REST] Add support for REST services

[Olshansk]

Objective

Add support for any REST service in PATH.

Origin Document

In pokt-network/poktroll/pull/879, we removed AppGateServer in the shannon repo in favor of PATH.

Part of this change meant removing support for REST because PATH does not have it yet.

Goals

• Add support for REST services
• Prepare for other protocols (gRPC, Websockets) in PATH
• Create an example set of PRs on how to add support for new protocol types: implementation, documentation, configs, examples, etc...

Deliverables

• Implement support for rest services
• Document a NEW page in path.grove.city explaining how to configure and use REST services
• Provide an example (cheatsheet + configs) on how to run a REST service in PATH
• Update the poktroll to revert all the TODOs added in pokt-
  network/poktroll/pull/879
  • Re-enable the LLM services
  • Re-enable the REST E2E tests

Non-goals / Non-deliverables

• TODO

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Creator: @Olshansk
Co-Owners: @commoddity @red-0ne