[Epic] Clean up LDAP and Google auth set-up experience

[ranquild]

Links

Product doc: https://www.notion.so/metabase/Clean-up-LDAP-and-Google-auth-set-up-experience-7499d138cf9845f9ab0b8fa459c1a7e1

Fixes

• https://github.com/metabase/metabase/issues/5555
• https://github.com/metabase/metabase/issues/16225
• https://github.com/metabase/metabase/issues/16363

Implementation plan

Milestone 1 - LDAP

• [ ] BE - https://github.com/metabase/metabase/pull/25421
• [ ] FE - https://github.com/metabase/metabase/pull/25439

Milestone 2 - Google Auth

• [ ] BE - Make it possible to configure and enable Google Auth separately (see the API changes below)
• [ ] FE - Add the Google Auth toggle to the card

API changes

Expose the following settings:

• ldap-configured - readonly setting; set to true when ldap settings have been validated and saved
• ldap-enabled - can be changed only when ldap-configured is true
• google-auth-configured - readonly setting; set to true when google auth settings have been validated and saved
• google-auth-enabled - can be changed only when google-auth-configured is true

Change POST /api/ldap/settings

• Remove ldap-enabled check, settings should be always validated
• Set ldap-configured to true when saved successfully
• Set ldap-enabled to true as well when previously ldap-configured was false

Add POST /api/google_auth/settings

• Accept google-auth-client-id and google-auth-auto-create-accounts-domain
• Perform the same validation when these settings are changed with /api/setting
• Set google-auth-configured to true when saved successfully
• Set google-auth-enabled to true as well when previously google-auth-configured was false