feat: format built in command

[jessicatarra]

Description

This PR introduces a new built-in command called "format" that follows the same implementation logic used in the development of the "analyze" command, which was merged in a previous (PR). The purpose of this change is to eliminate the need to set up a separate script in order to format each package.

For example, instead of using the following YAML configuration:

scripts:
  format:
    description: Format Dart code.
    run: dart format .

  format:check:
    description: Check formatting of Dart code.
    run: dart format --output none --set-exit-if-changed .

The first script can now be replaced with a simpler command: melos format. Similarly, the second script can be replaced with melos format --output none --set-exit-if-changed.

Additionally, this new command supports all melos filtering options and concurrency.

Dear maintainers, please feel free to review, modify, or add code to this contribution :)

Type of Change

• ✨ feat -- New feature (non-breaking change which adds functionality)
• 🛠️ fix -- Bug fix (non-breaking change which fixes an issue)
• ❌ ! -- Breaking change (fix or feature that would cause existing functionality to change)
• 🧹 refactor -- Code refactor
• ✅ ci -- Build configuration change
• 📝 docs -- Documentation
• 🗑️ chore -- Chore

[CLAassistant]

All committers have signed the CLA.

[spydon]

Two very minor comments, otherwise it looks good to me!

[spydon]

Looking forward to start using this!