refactor: migrate crosschain keeper

[kingpinXD]

Description

• Moves Node_Accounts, KeyGen, and Permission_Flags from cross-chain to observer module

• Adds a check for the observer set , which executes at every block, If this check fails (the observer set changes for some reason), It will
  - Pause Inbound Tx ( as new TSS will need to be generated)
  - Reset KeyGen back to pending status

• Once the inbound pauses, the following step would need to be done

  • Modify the node account list to remove/add new observers. (Can add a Policy based TX for this in a separate PR)
  • Set KeyGen Height for a new block to generate a new TSS

Closes:
#815
#830

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Include instructions and any relevant details so others can reproduce.

• Tested CCTX in localnet
• Tested in development environment
• Go unit tests
• Go integration tests
• Tested via GitHub Actions

Checklist:

• I have added unit tests that prove my fix feature works