feat: provide lean context config

[DavideMininni-Fincons]

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the pull request tracker for a Pull Request (PR) that matches the one I want to submit, without success.

Issue

This PR Closes #3010

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)

See Review Guidelines for more information what is checked during review process.

Changes

Changes in this pull request:

• the isLean function has been added: it checks if the document tag has the sbb-lean class;
• a new lean example page has been created under the page folder;
• the sbb-table in lean mode automatically takes the CSS rules of the sbb-table-s class;
• the following components has been modified in order to have the smallest size in lean mode:
  • sbb-accordion
  • sbb-action-group
  • sbb-alert
  • sbb-button
  • sbb-button-link
  • sbb-button-static
  • sbb-secondary-button
  • sbb-secondary-button-link
  • sbb-secondary-button-static
  • sbb-tertiary-button
  • sbb-tertiary-button-link
  • sbb-tertiary-button-static
  • sbb-transparent-button
  • sbb-transparent-button-link
  • sbb-transparent-button-static
  • sbb-mini-button
  • sbb-mini-button-group
  • sbb-card
  • sbb-checkbox
  • sbb-checkbox-group
  • sbb-checkbox-panel
  • sbb-dialog-actions
  • sbb-file-selector
  • sbb-file-selector-dropzone
  • sbb-form-field
  • sbb-header
  • sbb-journey header
  • sbb-link list
  • sbb-link list-anchor
  • sbb-block-link
  • sbb-block-link-button
  • sbb-block-link-static
  • sbb-link
  • sbb-link-button
  • sbb-link-static
  • sbb-navigation-button
  • sbb-navigation-link
  • sbb-navigation-list
  • sbb-navigation marker
  • sbb-notification
  • sbb-paginator
  • sbb-paginator-compact
  • sbb-radio-button
  • sbb-radio-button-group
  • sbb-radio-button-panel
  • sbb-skiplink-list
  • sbb-stepper
  • sbb-tab-group
  • sbb-tag
  • sbb-tag-group
  • sbb-toast
  • sbb-toggle
  • sbb-toggle-check
  • sbb-visual checkbox

Browsers

I tested the build on the following browsers:

• Firefox Desktop
• Chrome Desktop
• Edge Desktop
• Safari Desktop
• Chrome Mobile
• Safari Mobile

Screen readers

I tested the build on the following browsers:

• JAWS Firefox Desktop
• JAWS Chrome Desktop
• NVDA Firefox Desktop
• NVDA Chrome Desktop
• VoiceOver Safari Desktop
• VoiceOver Chrome Desktop
• VoiceOver Safari Mobile
• Android Accessibility Suite Chrome Mobile

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

Does this introduce a breaking change?

• Yes
• No

Other information

[jeripeierSBB]

Almost done! :) Found some cases

[jeripeierSBB]

LGTM, thanks a lot!