feat(css): styles for quote replies

* Remove padding from popup to make the button more sleek

* Reduce the default margin/padding on blockquotes to make nested quotes
look neater.

* Change text color within blockquotes to be a muted gray.

Author: palkerecsenyi

invenio_app_rdm/theme/assets/semantic-ui/less/invenio_app_rdm/theme/views/feed.overrides

@@ -78,6 +78,16 @@
 
     .text {
       width: auto;
+
+      &.extra blockquote {
+        margin-left: 0.5rem;
+        padding-left: 0.75rem;
+        color: @mutedTextColor;
+
+        & > blockquote {
+          margin-left: 0;
+        }
+      }
     }
 
     &.requests-action-event {
@@ -160,6 +170,7 @@
     border-left: @extraTextPointer;
     font-size: @extraTextFontSize;
     line-height: @extraTextLineHeight;
+
   }
 
   /*--------------
@@ -233,4 +244,11 @@
   }
 }
 
+.ui.popup.requests-event-body-popup {
+  padding: 0;
+  border: none;
 
+  .ui.button {
+    margin: 0;
+  }
+}