initial version of the query autocompletion

Missing features at this point:
1. No suggestions when the input gets the focus.
2. Suggestions are not shown after selecting a suggestion.

pdb-js/src/app/visualization-page/visualization-page.component.html

@@ -5,8 +5,8 @@
 
 <div id="visualization">
   <div id="query-box">
-      <input matInput placeholder="Query" value="{{query}}" />
-      <pdb-query-autocomplete></pdb-query-autocomplete>
+  <!-- [query]="query"-->
+      <pdb-query-autocomplete ></pdb-query-autocomplete>
   </div>
   <div id="filters">
     <mat-form-field class="mat-field-full-width">