Store filter/column settings in localStorage

The filter and column settings in tables are stored per project and
context in the browsers localStorage. This makes the table keep the
settings even if the browser is refreshed or restarted.

The table emits a "componentStateChanged" event containing the tables
current state (filter/column settings) which then is saved by the top
level component.

src/scripts/js/es6/common/vuecomponents/menu/DropDown.js

@@ -1,6 +1,6 @@
 const TEMPLATE =`
 <div class="pillar-dropdown">
-    <div class="pillar-dropdown-button"
+    <div class="pillar-dropdown-button action"
         :class="buttonClasses"
         @click="toggleShowMenu"
     >