sshca: Configure user CA

SSHCA now supports issuing user certificates.  It uses OpenID Connect to
authenticate requests, and issues certificates based on the user's ID
token.

authelia/configuration.yml

@@ -110,6 +110,17 @@ identity_providers:
       - email
       - groups
       - offline_access
+    - id: sshca
+      description: SSHCA
+      public: true
+      pre_configured_consent_duration: 4h
+      redirect_uris:
+      - http://127.0.0.1
+      scopes:
+      - openid
+      - profile
+      - email
+      - groups
 
 log:
   level: trace