REFACTOR: reworks all the search-advanced-options panel (#10661)

* REFACTOR: reworks all the search-advanced-options panel

This commit includes the following changes:
- prevents any mutation of external (to the component) values
- get rid of observers
- uses @action
- minor UI tweaks
- dropped the unecessary debounce
- drops all the legacy code for badges/groups which is not being used
- replaces user-selector by user-chooser and improves multi-select to not show `search` if maximum has been reached

Most importantly this refactor should fix multiple bugs due to _update() being called multiple times if searchTerm was empty and other various bugs where some changes in searchTerm was not applied to the sidebar.

app/assets/javascripts/select-kit/addon/components/multi-select/multi-select-header.js

@@ -11,6 +11,14 @@ export default SelectKitHeaderComponent.extend({
     return makeArray(this.selectedContent).map((c) => this.getName(c));
   }),
 
+  hasReachedMaximumSelection: computed("selectedValue", function () {
+    if (!this.selectKit.options.maximum) {
+      return false;
+    }
+
+    return this.selectedValue.length >= this.selectKit.options.maximum;
+  }),
+
   selectedValue: computed("selectedContent", function () {
     return makeArray(this.selectedContent)
       .map((c) => {