Added Monaco-based editor lite version

What does this MR do?

Introduces the basic Editor Lite version based on Monaco editor that is supposed to replace ACE in the single-filed editing interfaces (see Epic for more details).

What this MR does NOT do?

This MR does not contain any visual changes yet and is really a ~backstage one. It doesn't introduce any actual replacement of the ACE editor just yet as that is the concern of 3 dedicated issues:

• #198604 (closed)
• #198605 (closed)
• #198606 (closed)

Important note about the tests in this MR.

The tests for the Editor Lite are implemented in Karma instead of Jest because Jest is still not compliant with monaco-editor. See the relevant issue for more details.

Screenshots

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

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

Closes #198618 (closed)