Added SAML option for SSO authentication

[petruki]

This pull request introduces SAML 2.0 Single Sign-On (SSO) support as a new authentication provider, alongside improvements and bug fixes to the authentication flow and UI. The changes affect environment configuration, authentication services, login/signup components, and documentation to enable and surface SAML authentication throughout the application.

SAML 2.0 Authentication Integration

• Added SAML authentication support, including environment variables (ALLOW_SAML_AUTH), configuration handling, and UI logic to show/hide SAML login options based on environment settings. [1] [2] [3] [4] [5] [6] [7]
• Implemented SAML login flow in AuthService (loginWithSAMLToken), with corresponding logic in LoginComponent and SignupComponent to initiate SAML login and handle SAML tokens returned from the IdP. [1] [2] [3] [4]

UI/UX Enhancements for Auth Providers

• Updated login and signup forms to display SAML as an authentication option when enabled, including new SAML button and icon assets. [1] [2]
• Improved account settings to correctly display the provider-specific icon for SAML, Bitbucket, GitHub, or default.

Authentication Logic and Bug Fixes

• Refactored authentication provider detection to use the new auth_provider property, supporting SAML and fixing provider mapping logic.
• Fixed naming inconsistencies (onBitBucketLogin → onBitbucketLogin) and improved form validation and error handling in login/signup components. [1] [2] [3] [4]

Documentation Updates

• Expanded API documentation to include SAML 2.0 setup instructions and environment configuration for SSO, clarifying terminology and setup steps. [1] [2]

Other Improvements

• Updated development dependencies in package.json for Angular and TypeScript ecosystem.
• Enhanced user avatar styling in account settings. [1] [2]