Introduce syntax highlighting for .vue files

What does this MR do?

Issue: #212279 (closed)

Web IDE: Add support for .vue files

Add support for syntax highlighting .vue files in the Web IDE.

Note: This syntax highlighting is mostly based on handlebars template defined in monaco-languages. The support for vue-specific highlighting is included in this MR, but is very basic, and is meant to be a guideline for future contributions to improve syntax highlighting for the Web IDE.

Screenshots

Script	Style	Template

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