Refactor epoch function

[gztensor]

Description

We need this refactoring to prepare for a safe DTAO upgrade: Separate epoch and epoch_sparse functions into different parts:

1. Initialization
2. Running
3. Saving to storage

Also, split running into following functions to make it more testable and extendable:

1. fn calc_active_inactive(&mut self);
2. fn calc_validator_forbids(&mut self);
3. fn calc_active_stake(&mut self);
4. fn adjust_weights(&mut self);
5. fn calc_consensus(&mut self);
6. fn calc_ranks(&mut self);
7. fn calc_trust(&mut self);
8. fn calc_incentive(&mut self);
9. fn calc_bonds_and_dividends(&mut self);
10. fn calc_emission_and_pruning_scores(&mut self, rao_emission: u64);
11. fn calc_validator_trust(&mut self);
12. fn calc_new_validator_permits(&mut self);
13. fn adjust_ema_bonds(&mut self);
14. fn log_epoch(&self);

Related Issue(s)

n/a

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)
• [ ] Documentation update
• [x] Other (please describe): Refactoring

Breaking Change

none (hopefully :))

Checklist

• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have run cargo fmt and cargo clippy to ensure my code is formatted and linted correctly
• [ ] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [ ] Any dependent changes have been merged and published in downstream modules

Screenshots (if applicable)

n/a

Additional Notes

n/a