Use a key-value store model for sharing long queries (#1951)

* Add KeyValue model for storing id-value pairs
use it for storing shared queries

* Change string to text and added test

* Put getQueryLink in one place

* Changed migration down version

* Changes based on comments

* Update bcf3126872fc_add_keyvalue.py

superset/assets/javascripts/SqlLab/actions.js

@@ -298,3 +298,23 @@ export function removeTable(table) {
 export function refreshQueries(alteredQueries) {
   return { type: REFRESH_QUERIES, alteredQueries };
 }
+
+export function popStoredQuery(urlId) {
+  return function (dispatch) {
+    $.ajax({
+      type: 'GET',
+      url: `/kv/${urlId}`,
+      success: (data) => {
+        const newQuery = JSON.parse(data);
+        const queryEditorProps = {
+          title: newQuery.title ? newQuery.title : 'shared query',
+          dbId: newQuery.dbId ? parseInt(newQuery.dbId, 10) : null,
+          schema: newQuery.schema ? newQuery.schema : null,
+          autorun: newQuery.autorun ? newQuery.autorun : false,
+          sql: newQuery.sql ? newQuery.sql : 'SELECT ...',
+        };
+        dispatch(addQueryEditor(queryEditorProps));
+      },
+    });
+  };
+}