Ensure that diff stats can scroll independently of the diff (#8581) (#8611)

This PR ensures that once opened the diff stats detail box can be scrolled independently of the diff on the compare page.

Fixes #5532 

Details:

* make diff-detail-box the main container
* move file diff at the same level as diff-stats
* make diff-view options sticy again
* make diff-stats scroll if to mouch
* rm useless css info
* less: mv diff-stats to own class
* use new css class
* cleanup less file
* diff-counter: margin-right: 15px;
* make CI work
* make numbers colorful
* add sign (-/+) to numbers

public/less/_repository.less

@@ -1237,21 +1237,6 @@
             display: block;
         }
 
-        ol {
-            clear: both;
-            padding-left: 0;
-            margin-top: 5px;
-            margin-bottom: 28px;
-
-            li {
-                list-style: none;
-                padding-bottom: 4px;
-                margin-bottom: 4px;
-                border-bottom: 1px dashed #dddddd;
-                padding-left: 6px;
-            }
-        }
-
         span.status {
             display: inline-block;
             width: 12px;
@@ -1466,6 +1451,34 @@
         }
     }
 
+    .diff-stats {
+
+        clear: both;
+        margin-bottom: 5px;
+        max-height: 400px;
+        overflow: auto;
+        padding-left: 0;
+
+        li {
+            list-style: none;
+            padding-bottom: 4px;
+            margin-bottom: 4px;
+            border-bottom: 1px dashed #dddddd;
+            padding-left: 6px;
+        }
+
+        .diff-counter {
+            margin-right: 15px;
+
+            .del {
+                color: red;
+            }
+            .add {
+                color: green;
+            }
+        }
+    }
+
     .repo-search-result {
         padding-top: 10px;
         padding-bottom: 10px;