Standard title configurable

What does this MR do?

Our users are LDAP based and we use "Standard" log-in for "external" users only. Title "Standard" is misleading so users tend to use "Standard" log-in. This MR enables "Standard" title to be renamed within configuration.

Original:

With standard title alias configuration parameter in /etc/gitlab/gitlab.rb like gitlab_rails['standard_title'] = 'External Users' it looks like this:

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer