Add option to specify which events to listen for in `listen` command

[ancazamfir]

Crate

ibc-relayer-cli

Summary

Add flag to rrly -c loop_config.toml listen ibc-0 command to specify which events to listen for.

Problem Definition

We are often not interested in NewBlock events, and would like to filter them out to only keep Tx events.

Proposal

USAGE:
    hermes listen <OPTIONS>

DESCRIPTION:
    Listen to and display IBC events emitted by a chain

POSITIONAL ARGUMENTS:
    chain_id                  Identifier of the chain to listen for events from

FLAGS:
    -e, --event EVENT         Add an event type to listen for, can be repeated. Listen for all events by default (available: Tx, NewBlock)

---

Listen for default events:

$ hermes listen ibc-0
[info ] Listening for events `NewBlock, Tx` on 'ibc-0'...

Listen for NewBlock event only:

$ hermes listen ibc-0 -e NewBlock
[info ] Listening for events `NewBlock` on 'ibc-0'...

Listen for NewBlock and Tx events:

$ hermes listen ibc-0 -e NewBlock -e Tx
[info ] Listening for events `NewBlock, Tx` on 'ibc-0'...

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For Admin Use

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