Add docs links to Feature Flags strategy settings

What does this MR do?

This MR addresses #225453 (closed) by introducing the following parts to better clarify Feature Flags strategy settings:

• update / add wording (visible from the .pot file)
• add links to documentation for relevant section by provide/inject strategy in order not to pass them along the children chain

Note: old FF layout is not targeted by the changes.

Additionally, the Strategy Component markup classes are updated with GitLab UI Utilities. For the ones that were not possible to update (because of the missing utilities) a follow-up Issue has been created.

Screenshots

FF New Layout

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team