Setup GraphQL mutations to add and verify email addresses

This refactors a bit how the connection to the repository is done in the
graphql handler, so that we can properly commit transactions.

crates/graphql/src/state.rs

@@ -0,0 +1,41 @@
+// Copyright 2023 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file 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.
+
+use mas_data_model::BrowserSession;
+use mas_storage::{BoxClock, BoxRepository, BoxRng, RepositoryError};
+
+#[async_trait::async_trait]
+pub trait State {
+    async fn repository(&self) -> Result<BoxRepository, RepositoryError>;
+    fn clock(&self) -> BoxClock;
+    fn rng(&self) -> BoxRng;
+}
+
+pub type BoxState = Box<dyn State + Send + Sync + 'static>;
+
+pub trait ContextExt {
+    fn state(&self) -> &BoxState;
+
+    fn session(&self) -> Option<&BrowserSession>;
+}
+
+impl ContextExt for async_graphql::Context<'_> {
+    fn state(&self) -> &BoxState {
+        self.data_unchecked::<BoxState>()
+    }
+
+    fn session(&self) -> Option<&BrowserSession> {
+        self.data_opt()
+    }
+}