feature: add `/clear_all` in exposer to clear all packets on the relayer

## Overview
Sometime the packets are stuck, exposing the ability to clear the packets on a timely interval can then be achived with a new endpoint in exposer that can clear all packets

## Design
Runs following command in the backend:
```
hermes clear packets --chain cosmoshub-4 --port wasm.cosmos17r3faruez552kdxy0lsjydmj0nu22mxax33azx326039hfe7pnhqy7ztdu --channel channel-2
```

Might need to fetch the information about the channels and ports for the chains from the chain registry.

NOTE: chain registry will also have channels that are currently stuck.