Editor: New line on Enter, run query on Shift+Enter (#24654)

* Editor: New line on Enter, run query on Shift+Enter

- default Enter behavior on query editor fields should be a new line
- special behavior should require a special key: running a query is now
done on Shift-Enter
- Plugins order had to be changed because when typeahead is shown, Enter
is accepting the suggestion

* Run with ctrl-enter, hint in query placeholder

* Fix Kusto field behavior for Enter

* Fix Kusto field behavior for default suggestion

public/app/plugins/datasource/prometheus/components/PromQueryField.tsx

@@ -340,7 +340,7 @@ class PromQueryField extends React.PureComponent<PromQueryFieldProps, PromQueryF
               onBlur={this.props.onBlur}
               onChange={this.onChangeQuery}
               onRunQuery={this.props.onRunQuery}
-              placeholder="Enter a PromQL query"
+              placeholder="Enter a PromQL query (run with Shift+Enter)"
               portalOrigin="prometheus"
               syntaxLoaded={syntaxLoaded}
             />