[Glitch] Use local instead of global loading indicator for timelines, account timelines

Port dd00cd19d2 to glitch-soc

app/javascript/flavours/glitch/styles/components/index.scss

@@ -597,6 +597,16 @@
   @supports(display: grid) { // hack to fix Chrome <57
     contain: strict;
   }
+
+  &--flex {
+    display: flex;
+    flex-direction: column;
+  }
+
+  &__append {
+    flex: 1 1 auto;
+    position: relative;
+  }
 }
 
 .scrollable.fullscreen {