Light client extraction (long-lived branch)

[hu55a1n1]

Closes: #2338

Description

This is the PR for merging the long-lived branch for ADR011 impl.

Make sure the following points are addressed before merging ->

• [ ] ChannelReaderLightClient is a supertrait of ChannelReader. (see comment -> https://github.com/informalsystems/ibc-rs/pull/2332#discussion_r932524874)
• [ ] Remove encode_vec()
• [ ] Add CI test for dummy light client that is hosted in an external crate (similar to https://github.com/informalsystems/ibc-rs/tree/master/ci/no-std-check).

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PR author checklist:

• [ ] Added changelog entry, using unclog.
• [ ] Added tests: integration (for Hermes) or unit/mock tests (for modules).
• [ ] Linked to GitHub issue.
• [ ] Updated code comments and documentation (e.g., docs/).
• [ ] Tagged one reviewer who will be the one responsible for shepherding this PR.

Reviewer checklist:

• [ ] Reviewed Files changed in the GitHub PR explorer.
• [ ] Manually tested (in case integration/unit/mock tests are absent).