get rid of global notify (#5355)

* [toasts] get rid of notify globals, refactor messageToasts for use by entire app

* [remove notify] use arrow func in ajax call

* fix lint + tests

* actually fix tests from messageToast refactor

* add 'test:one' npm script

* debugger

* [toasts] convert bootstrap flash messages to toasts in explore + sqllab

* [toasts][tests] import from right file

superset/assets/spec/javascripts/sqllab/SqlEditor_spec.jsx

@@ -11,7 +11,7 @@ describe('SqlEditor', () => {
   const mockedProps = {
     actions: {},
     database: {},
-    queryEditor: initialState.queryEditors[0],
+    queryEditor: initialState.sqlLab.queryEditors[0],
     latestQuery: queries[0],
     tables: [table],
     queries,