Move some shared code to `members` directory [RUN AS-IF-FOSS]

What does this MR do?

In &4233 (closed) we converted the group members view from HAML to Vue to improve the UX. Now I am working on giving the same treatment to the project members view. I am finding some code that was originally put in the groups/members directory but I am realizing this code can be used for the project members view. This MR moves that code from groups/members directory to the members directory.

Summary of changes

• Move app/assets/javascripts/groups/members/components/app.vue to app/assets/javascripts/members/components/app.vue
• Move a few shared utilities from app/assets/javascripts/groups/members/utils.js to app/assets/javascripts/members/utils.js
• Move a few shared constants from app/assets/javascripts/groups/members/constants.js to app/assets/javascripts/members/constants.js
• Move a few shared EE utilities from ee/app/assets/javascripts/groups/members/utils.js to ee/app/assets/javascripts/members/utils.js
• Rename data-group-id to data-source-id in !51520 (diffs)
  • For group members this value is group.id. For project members this value will be project.id. source is a naming convention that is used on the backend so seems like the best name here.
• Rename linked_groups_data_json and linked_groups_list_data_attributes helper methods to group_group_links_data_json and group_group_links_list_data_attributes.
  • To better match the naming convention used by the backend in the group_group_link model. Also to avoid name clashing when we add the project member helpers. The project member helper names will be project_group_links_data_json and project_group_links_list_data_attributes

Screenshots (strongly suggested)

No visual changes. Screenshots below for context:

Before	After

Local testing

1. Create a group
2. Navigate to Group -> Members

How to add a group

1. Navigate to Group -> Members
2. Click the Invite group tab

How to add an invited member

1. Navigate to Group -> Members
2. In the GitLab member or Email address enter an email that a user does not already own
3. Click Invite "example@test.com" by email

How to request access to a project

1. Log in (or impersonate) a user that doesn't already have access to the group
2. Navigate to the group overview
3. Click Request access located below the project name

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

Related to #281815 (closed)