Geo Settings Form - Remove Old Code

What does this MR do?

Closes #216134 (closed)

This MR is an attempt at MVC to avoid the above massive MR going in all at once.

This MR removes the feature flag :enable_geo_settings_form_js

This MR removes the need for a feature flag and removes the old HAML form. Essentially this is just removing all the old code and activating the new form in JavaScript for everyone.

Breakdown of MRs

More information can be found here: #216134 (comment 354619867)

This is MR 5 of 5 to fully implement and replace the Geo Settings Form from HAML -> Vue

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