lp-gateway: Add extrinsics for initiating and disputing message recovery

[cdamian]

Description

Added:

• new extrinsics for initiating and disputing message recovery.
• new gateway events when processing inbound and outbound messages.

Changed:

• renamed LPEncoding to LPMessage.
  • added new methods from getting dispute messages.
  • changed message hash method.

Checklist:

• [x] I have added Rust doc comments to structs, enums, traits and functions
• [x] I have made corresponding changes to the documentation
• [x] I have performed a self-review of my code
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] Added extra events for LP gateway, LP.
• [x] Removed sender field for outbound gateway message.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 74.32432% with 19 lines in your changes missing coverage. Please review.

Project coverage is 48.96%. Comparing base (771fb78) to head (b3f2f07). Report is 1 commits behind head on main.

Files	Patch %	Lines
.../liquidity-pools-gateway/src/message_processing.rs	72.72%	9 Missing :warning:
pallets/liquidity-pools/src/message.rs	0.00%	7 Missing :warning:
pallets/liquidity-pools-gateway/src/lib.rs	91.17%	3 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1970 +/- ## ========================================== + Coverage 48.86% 48.96% +0.10% ========================================== Files 183 183 Lines 13095 13133 +38 ========================================== + Hits 6399 6431 +32 - Misses 6696 6702 +6 ```

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[cdamian]

@lemunozm @wischli can we go ahead and merge it since everything is green? We can tackle the other item in a separate PR.