Move members JS from `vue_shared` to main JS directory [RUN AS-IF-FOSS]

What does this MR do?

Related to #263670 (closed) and !44503 (comment 425582909)

Though the vue_shared/components/members will be used by the group and project views it doesn't necessarily make sense for them to live in vue_shared. This MR moves it to javascripts/members.

This JS is currently responsible for rendering the group members view. In the future it will also be used to render the project members view.

Screenshots (strongly suggested)

No visual changes

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
  • Not needed, developer facing change
• [-] 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