feat(sequencers): sequencer rotation support

[mtsitrin]

Closes #993

will be done separately:

• [x] https://github.com/dymensionxyz/dymension/issues/1025
• [x] #1026

Summary by CodeRabbit

• New Features

  • Enhanced functionality for querying current and next proposers of rollapps.
  • Introduced parameters for unbonding time and notice period for sequencers in genesis configuration.
  • Added new methods for managing sequencer rotations and notice periods.

• Bug Fixes

  • Improved error handling and clarity for sequencer registration and unbonding processes.

• Documentation

  • Enhanced comments across various files for better understanding of code logic and structure.

• Style

  • Refactored code for improved readability and consistency in method naming and logic flow.

• Tests

  • Expanded test coverage for sequencer management and proposer rotations.
  • Refactored tests to improve clarity and maintainability.