Add external identity login

[DmyMi]

• [x] Add external login functionality with gov provider.
• [x] Integrated external flow with OpenIdDict OAuth2 flow.
• [x] Add creation of User & Individual entities for external flow
• [x] Add new UI view
• [x] Add feature management to hide obsolete flows for now
• [x] Add Microsoft Resiliency instead of Custom code for HttpClient
• [x] Added a new buildpack to pack external CAs with group writable permissions according to RFC-0045
• [ ] Add localization
• [ ] Improve error handling & display for end user

[sonarcloud[bot]]

Quality Gate failed

Failed conditions
3 Security Hotspots
48.1% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud