[v6] Implement Realtime Database (#2195)

* [database] recreate database branch based off of #2185

* [database] cleanup linting issues

* [database] enable tests

* [database] add to tests deps

packages/database/e2e/query/toJSON.e2e.js

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2016-present Invertase Limited & Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this library except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+describe('database().ref().toJSON()', () => {
+  it('returns a string version of the current query path', async () => {
+    const res = firebase
+      .database()
+      .ref('foo/bar/baz')
+      .toJSON();
+    const expected = `${firebase.database()._customUrlOrRegion}/foo/bar/baz`;
+    should.equal(res, expected);
+  });
+});