Introduce option to use individual Apollo requests

What does this MR do?

Introduce option to use individual Apollo requests

This MR introduces an option on the Apollo client which allows a developer to specify if they'd rather make use of single requests instead of having all requests batched.

This introduces a performance benefit when a Vue component has data which needs to be returned from multiple queries, and some of the queries are potentially long running.

Screenshots

Note the visual changes of each loading icon completing individually in the second example. This results in a faster time to first visual change.

Batch requests only	Individual requests
Screen_Recording_2020-08-18_at_13.25.54	Screen_Recording_2020-08-18_at_13.28.34

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

Related issue

#232651 (closed)