[WEB-5324] refactor: add Unified OAuth Configuration and Missing Gitea Options (#8050)

* refactor: add Unified OAuth Configuration and Missing Gitea Options

- Replaced the AuthenticationModes component with a more streamlined implementation using AuthenticationMethodCard.
- Removed obsolete authentication modes files from the codebase.
- Enhanced the AuthRoot component to utilize the new OAuth configuration hook for better management of authentication options.
- Updated type definitions for instance authentication modes to reflect the new structure.

* refactor: update OAuth type imports and remove obsolete types

- Replaced local type imports with centralized imports from @plane/types in core, extended, and index OAuth hooks.
- Removed the now redundant types.ts file as its definitions have been migrated.
- Enhanced type definitions for OAuth options to improve consistency across the application.

* feat: add new Gitea logo and update OAuth icon imports to use standard HTML img tags

* chore: remove unused authentication logos and upgrade button component

Author: prateekshourya29