Refactor modules structure to make it more domain-related instead of function-related

[carbolymer]

Changelog

- description: |
    Refactor modules structure to make it more domain-related instead of function-related
# uncomment types applicable to the change:
  type:
  # - feature        # introduces a new feature
  # - breaking       # the API has changed in a breaking way
  # - compatible     # the API has changed but is non-breaking
  # - optimisation   # measurable performance improvements
   - refactoring    # QoL changes
  # - bugfix         # fixes a defect
  # - test           # fixes/modifies tests
  # - maintenance    # not directly related to the code
  # - release        # related to a new release preparation
  # - documentation  # change in code docs, haddocks...

Context

Change to domain-related modules structure

The present cardano-cli modules structure is as follows:

Cardano/CLI
├── Byron
├── Commands
├── EraBased
│   ├── Commands
│   │   └── Governance
│   │       └── Committee.hs
│   ├── Options
│   │   └── Governance
│   │       └── Committee.hs
│   └── Run
│       └── Governance
│           └── Committee.hs

it's spread across many different modules: Commands.Governance , Options.Governance, Run.Governance and multiple Types.Errors.GovernanceXXX. So right now you have to jump between different places to find code related to Committee, which is cumbersome.
Any future refactoring related to a single command would also require changes in three different places.

This PR changes the structure by 90 degrees and putting code into separate-ish domains instead, for example changing the above structure into this:

Cardano/CLI
├── Byron
├── Commands
├── EraBased
│   └── Governance
│       └── Committee
│           ├── Commands.hs
│           ├── Options.hs
│           └── Run.hs

(We could get rid of EraBased if there's a more elegant alternative).

This way you have everything related to a single command in one place which makes codebase easier to understand.

Aggregation of era independent commands

Additionally, era independent commands like address or hash are placed into Cardano.CLI.EraIndependent module to reduce clutter in Cardano.CLI module.

Use of singular nouns for module names

All module names which had plural nouns are renamed to use singular nouns in their names.

Comparison

Before:

After:

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff

[smelc]

Big change! This is one that @Jimbo4350 should approve 🙂

[palas]

I went through the whole thing and I am pretty confident no code disappeared and no new code appeared. So, if it compiles, I think it is indeed a refactoring. But, I will leave approval to @Jimbo4350