Auth: Azure AD OAuth (#20030)

* Implement Azure AD oauth

* Use go-jose and cleanup

* Update go-jose in go.mod

* cleanup

* Add unit tests

* Fix scopes

* Add documentation page

* Improve documentation

* Convert extract_role into function.

* Do not use upn and replace unique_name with preferred_username

* Configure login button

* Use official microsoft icon and color from branding guideline.

* Add Azure AD config section in sample.ini.

public/app/core/components/Login/LoginServiceButtons.tsx

@@ -15,6 +15,10 @@ const loginServices: () => LoginServices = () => {
       enabled: oauthEnabled && config.oauth.google,
       name: 'Google',
     },
+    azuread: {
+      enabled: config.oauth.azuread,
+      name: 'Microsoft',
+    },
     github: {
       enabled: oauthEnabled && config.oauth.github,
       name: 'GitHub',