finality-provider: refactor, tests, fixes and chore

[bap2pecs]

Refactor

• babylonchain/finality-provider#491
• move a few test-only functions to tests e.g. QueryFinalityProviders

Tests

• babylonchain/finality-provider#403
• babylonchain/finality-provider#487
• babylonchain/finality-provider#449
• babylonchain/finality-provider#439
• babylonchain/finality-provider#415
• babylonchain/finality-provider#414
• babylonchain/finality-provider#397
• babylonchain/finality-provider#346
• babylonchain/finality-provider#345
• babylonchain/finality-provider#343

Fixes

• babylonchain/finality-provider#478
• babylonchain/finality-provider#463

Chore

• babylonchain/finality-provider#475
• babylonchain/finality-provider#464
• babylonchain/finality-provider#457
• babylonchain/finality-provider#353
• babylonchain/finality-provider#349

[bap2pecs]

@SebastianElvis most of the tasks here are irrelevant to the OP integration. they are more like good-to-have low-pri improvements.

feel free to take a look and close this EPIC issue. for anything yo think are still useful, maybe you can create another task in the FP repo, such as "Miscellaneous Improvements".