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/utils/common.js

@@ -39,8 +39,20 @@ export function getParamFromQuery(query, param) {
   return null;
 }
 
-export function getLink(baseUrl, params) {
-  return baseUrl + '?' + params.join('&');
+export function storeQuery(query, callback) {
+  $.ajax({
+    type: 'POST',
+    url: '/kv/store/',
+    async: false,
+    data: {
+      data: JSON.stringify(query),
+    },
+    success: (data) => {
+      const baseUrl = window.location.origin + window.location.pathname;
+      const url = `${baseUrl}?id=${JSON.parse(data).id}`;
+      callback(url);
+    },
+  });
 }
 
 export function getParamsFromUrl() {