feat(cli): split cli into sub commands

[avivkeller]

Description

This PR splits the CLI into subcommands, following the structure shown below:

api-docs-tooling
│
├── generate       → Generate API docs
├── lint           → Run linter independently
├── list
│   ├── generators → List available generators
│   ├── rules      → List available linter rules
│   └── reporters  → List available reporters
├── interactive    → Launch a guided CLI wizard

Validation

Every command shown in the updated README should work as intended.

Related Issues

Fixes #148

Check List

• I have read the Contributing Guidelines and made commit messages that follow the guideline.
• I've covered new added functionality with unit tests if necessary.

[avivkeller]

Ack! I never rebased the multi-threading

[avivkeller]

Self-review on things I need to verify/fix

[AugustinMauroy]

From a DX point of view, do we want to have commands that are just keyword like list or should they all be flags like --list?
I'm fine with both

[avivkeller]

From a DX point of view, do we want to have commands that are just keyword like list or should they all be flags like --list?

As @ovflowd stated in the linked issue,

There should be a simple top-level command called list to list the current generators. (Version, Name, Description, Examples)

I like the idea of splitting each different function into these subcommands, I feel it makes it easier to understand what does what.

[avivkeller]

Requesting review from @ovflowd, who opened the issue