Add name_regex_keep param to tag bulk delete api

What does this MR do?

Adds a new param name_regex_keep to the container registry bulk tag delete api endpoint and renames the existing name_regex to name_regex_delete.

name_regex_keep will override name_regex_delete when the CleanupTagsService selects tags for deletion.

For example, if I have

name_regex_delete = '.*'
name_regex_keep = 'myTag.*'

All tags will be deleted except for ones starting with myTag. If .* is passed as the value for both, they cancel each other out and nothing is deleted.

Another way to look at this is if name_regex_keep = '.*, then it will not matter what name_regex_delete is set to because name_regex_keep will match all tags, causing everything to be retained.

Screenshots

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 #27072 (closed)