Review SCSS refactoring for to-be-deprecated Bourbon functions (#1959)

* [Frontend] Refactor SCSS to remove deprecated @includes

Fixes #1891
- In progress

* [Frontend] Refactor SCSS to remove deprecated @includes

Fixes #1891
Making bourbon happy by refactoring to-be-deprecated
calls to prefixing @includes:
- transform and related CSS;
- flex and related CSS;
- Fixed double semi-colons to single;

platform/features/timeline/res/sass/_timeline-thematic.scss

@@ -53,7 +53,7 @@
             width: $d;
             position: absolute;
             top: 0;
-            @include transform(translateX(-50%));
+            transform: translateX(-50%);
         }
         &:before {
             // Icon blocker

platform/features/timeline/res/sass/_timelines.scss

@@ -177,7 +177,7 @@
 		            top: 20px; bottom: 5px;
 		            .l-labels-holder {
 			            @include absPosDefault();
-                        @include justify-content(space-between);
+                        justify-content: space-between;
 			            left: $m;
 			            .t-resource-graph-tick-label {
                             font-size: 0.9em;