feat(auth): Allow to hide username / password login form when OAuth is enabled (#518)

* 🚀 Feature: Allow to hide username / password login form when OAuth is enabled

* Hide “Sign in” password form
* Disable routes related to password authentication
* Change styling of OAuth provider buttons
* Open OAuth page in same tab
* Fix consistent usage of informal language in de-DE locale

Fixes #489

Signed-off-by: Marvin A. Ruder <signed@mruder.dev>

* fix: order of new config variables

---------

Signed-off-by: Marvin A. Ruder <signed@mruder.dev>
Co-authored-by: Elias Schneider <login@eliasschneider.com>

frontend/src/i18n/translations/en-US.ts

@@ -44,6 +44,7 @@ export default {
   "signIn.notify.totp-required.description":
     "Please enter your two-factor authentication code",
   "signIn.oauth.or": "OR",
+  "signIn.oauth.signInWith": "Sign in with",
   "signIn.oauth.github": "GitHub",
   "signIn.oauth.google": "Google",
   "signIn.oauth.microsoft": "Microsoft",
@@ -479,6 +480,9 @@ export default {
   "admin.config.oauth.ignore-totp": "Ignore TOTP",
   "admin.config.oauth.ignore-totp.description":
     "Whether to ignore TOTP when user using social login",
+  "admin.config.oauth.disable-password": "Disable password login",
+  "admin.config.oauth.disable-password.description":
+    "Whether to disable password login\nMake sure that an OAuth provider is properly configured before activating this configuration to avoid being locked out.",
   "admin.config.oauth.github-enabled": "GitHub",
   "admin.config.oauth.github-enabled.description":
     "Whether GitHub login is enabled",