Infrastructure and changes to the Query Tool for realtime preference handling. Refs #3294

Highlights of this patch include:
- Changes will affect SQL Editors in Create dialog boxes, SQL tab of the main screen, Query tool, History entries in the query tool, Query tool opened in New Tab/Window
- All the components of SQL editor will refer to single source of preferences which is cached in the Browser object. All other redundant ajax get preference calls are removed.
- SQL editor will not refer template JS variables anymore, once all the references are removed the template variables will also be removed.
- Code refactoring wherever possible.
- Covered JS test cases wherever possible.

web/pgadmin/static/jsx/history/detail/code_mirror.jsx

@@ -50,6 +50,11 @@ export default class CodeMirror extends React.Component {
     Object.keys(props.options || {}).forEach(key => this.editor.setOption(key, props.options[key]));
 
     this.editor.setValue(props.value || '');
+
+    if(props.sqlFontSize) {
+      $(this.editor.getWrapperElement()).css('font-size', props.sqlFontSize);
+    }
+
     this.editor.refresh();
   }
 

web/pgadmin/static/jsx/history/detail/history_detail_query.jsx

@@ -64,6 +64,7 @@ export default class HistoryDetailQuery extends React.Component {
             mode: 'text/x-pgsql',
             readOnly: true,
           }}
+          sqlFontSize= {this.props.sqlEditorPref.sql_font_size}
         />
       </div>);
   }
@@ -71,4 +72,5 @@ export default class HistoryDetailQuery extends React.Component {
 
 HistoryDetailQuery.propTypes = {
   historyEntry: Shapes.historyDetail,
+  sqlEditorPref: Shapes.sqlEditorPrefObj,
 };

web/pgadmin/static/jsx/history/query_history.jsx

@@ -97,13 +97,16 @@ export default class QueryHistory extends React.Component {
           selectedEntry={this.state.selectedEntry}
           onSelectEntry={this.selectHistoryEntry}
         />
-        <QueryHistoryDetail historyEntry={this.state.currentHistoryDetail}/>
+        <QueryHistoryDetail historyEntry={this.state.currentHistoryDetail}
+            sqlEditorPref={this.props.sqlEditorPref}
+        />
       </SplitPane>);
   }
 }
 
 QueryHistory.propTypes = {
   historyCollection: Shapes.historyCollectionClass.isRequired,
+  sqlEditorPref: Shapes.sqlEditorPrefObj,
 };
 
 export {