feat: add interchain token service encoding/decoding api

[milapsheth]

Description

AXE-4071

Todos

• [x] Unit tests
• [ ] Manual tests
• [ ] Documentation
• [ ] Connect epics/issues

Steps to Test

Expected Behaviour

Other Notes

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 88.84381% with 55 lines in your changes missing coverage. Please review.

Project coverage is 93.93%. Comparing base (770a488) to head (aa5ad3a).

Files	Patch %	Lines
interchain-token-service/src/abi.rs	89.33%	51 Missing :warning:
interchain-token-service/src/primitives.rs	71.42%	4 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #482 +/- ## ========================================== - Coverage 94.03% 93.93% -0.10% ========================================== Files 186 189 +3 Lines 26184 26677 +493 ========================================== + Hits 24622 25060 +438 - Misses 1562 1617 +55 ```

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