feat: Implement oauth2 monitors (#3119)

* [empty commit] pull request for implement oauth2 monitor

* feat: implement oauth2 client credentials flow

* fix: auth methods clarification & error handling

* docs: fix JSdocs types and clarifications

package.json

@@ -118,6 +118,7 @@
         "nodemailer": "~6.6.5",
         "nostr-tools": "^1.13.1",
         "notp": "~2.0.3",
+        "openid-client": "^5.4.2",
         "password-hash": "~1.2.2",
         "pg": "~8.8.0",
         "pg-connection-string": "~2.5.0",