Set up basic Vue app + GraphQL + Apollo

What does this MR do?

Second MR in the plan for #34820 (closed). Hence ⚠ this should not close original issue (though merging in master should happen) as the development happens behind the feature flag

The MR introduces basic Vue placeholder application with support for GraphQL and Apollo. There's no visible change in this MR, hence no screenshots are provided.

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

References #34820 (closed)