Merge branch '50020-fe-allow-email-notifications-to-be-disabled-for-all-users-of-a-group' into 'master'

UI for disabling group/project email notifications

Closes #50020

See merge request gitlab-org/gitlab-ce!30961

(cherry picked from commit 1068483f)

7699a87e UI for disabling group/project email notification
bad143ff Rename canChangeEmailsDisabled to canDisableEmails
38b3f9ec Hide emails_disabled checkbox if disabled in group
5e1fc2f5 Apply suggestion to...
bcd5cee9 Addressed review feedback
d602fc12 Minor fixes for gitlab.pot
1ee32758 Update permissions documentation
43c87103 Vue file prettified
e5ec00ce Apply suggestion to app/views/shared/notifications/_button.html.haml
e2de0db9 Disable the subgroup checkbox
dbd7fcbd Add checked to emails_disabled group settings

- Select notification email by walking up group/subgroup path
- Add settings UI to set group email notification address
- Add tests

- Avatar, group name, and group description now left-aligned
- Notification setting and "New project" CTA right-aligned
  with group avatar and name
- Leave group / request access now a link next to the 'Group'
  label below the group name
- Notification setting label removed in favor of icons
  - Tooltip added to indicate notification setting
- Search option moved inside table header next to "Sort by"

Continues the iteration on the project overview UI:

- moved star, fork and new clone button
(copy SSH/HTTPS URLs) to top right,
  made them smaller
- avatar is now larger (64px)
- 'Request access' is now a link instead
  of a button
- overview comes before the description +
  changed styling and added icons
- description font-size is now 16px (large-paragraph)
- quick links to files are moved downwards
  below the commit/pipeline info
- margins changed to group content into
  4 groups to clean up the interface
- visibility info reduced to icon-only and
  moved to the right of the title

Bring back "notification-dropdown" class for styling and use "js-notification-dropdown" for JavaScript