Add client_id support for OpenID (#8579)

- One click OpenID authorization on Login page
- Add client_id help, config keys etc

Thanks to @egorkaru @ihostage for the
original work and testing.

browser/app/less/inc/login.less

@@ -101,14 +101,15 @@
 
 .openid-btn {
     display: inline-block;
+    color: @link-color;
     margin-top: 30px;
     border-width: 1px;
     border-style: solid;
     opacity: 0.6;
     font-size: 14px;
     &:hover {
-        color: @link-color;
         opacity: 1;
+        cursor: pointer;
     }
 }
 
@@ -118,7 +119,7 @@
     align-items: center;
     color:grey;
   }
-  
+
 .or:after,
 .or:before {
     content: "";
@@ -136,4 +137,4 @@ input:-webkit-autofill {
      -webkit-box-shadow:0 0 0 50px #002a37 inset !important;
      -webkit-text-fill-color: @white !important;
     caret-color: white;
-}
+}