Add editor-color-palette-bootstrap4.json

[IanDelMar]

Description

This PR adds editor-color-palette-bootstrap4.json which permanently holds the Bootstrap 4 color palette. editor-color-palette.json now permanently holds the Bootstrap 5 color palette.

Fixes the color palette for Bootstrap 5 and most likely increases color related accessibility.

Motivation and Context

See #2028

Types of changes

• 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 change)
• Refactoring (a code change that neither fixes a bug nor adds a feature)
• Styling (changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc))
• Development (changes that affect the build system or external dependencies)
• Documentation (changes that affect existing inline documentation)

Breaking/changing the default styles for users who are currently using Bootstrap 5 as they now get the Bootstrap 5 palette instead of the Bootstrap 4 palette.

Checklist:

• I pulled my branch from develop.
• I am submitting my pull request to develop.
• I have resolved any conflicts merging this pull request would create.
• I have checked that there aren't other open Pull Requests for the same update/change.
• My code follows the code style of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• (Optional) My change requires a change to the documentation.
• (Optional) I have updated the documentation accordingly.
• (Optional) My change requires a change to the translations.
• (Optional) I have updated the translations accordingly.
• composer phpcs has passed locally.
• composer php-lint has passed locally.
• composer phpmd has passed locally.
• composer phpstan has passed locally.
• I have read the CONTRIBUTING document.

Related Issues or Roadmap requests

Closes #2028

Further comments

This PR is waiting for bacoords/postcss-understrap-palette-generator#4 to be merged.

TODO:
1. Update postcss-understrap-palette-generator dependency.
2. Generate separate JSON files.

[bacoords]

The other PR has been merged so this is ready to be updated with the new JSON file!

[IanDelMar]

I updated the json files.