Add routing for call page

Enable buttons to start a call.
Improve ConversationListItem context menu layout.
Move calling buttons from `Button.tsx` to `CallButtons.tsx`.
Add CallProvider

GitLab: #78
Change-Id: I921aa11383bf39fae18e59b01afb00dc66b0d5e6
diff --git a/client/src/contexts/CallProvider.tsx b/client/src/contexts/CallProvider.tsx
new file mode 100644
index 0000000..0716c8c
--- /dev/null
+++ b/client/src/contexts/CallProvider.tsx
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2022 Savoir-faire Linux Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public
+ * License along with this program.  If not, see
+ * <https://www.gnu.org/licenses/>.
+ */
+import { createContext, useState } from 'react';
+
+import { SetState, WithChildren } from '../utils/utils';
+
+interface ICallContext {
+  micOn: boolean;
+  setMicOn: SetState<boolean>;
+  camOn: boolean;
+  setCamOn: SetState<boolean>;
+}
+
+const defaultCallContext: ICallContext = {
+  micOn: false,
+  setMicOn: () => {},
+  camOn: false,
+  setCamOn: () => {},
+};
+
+export const CallContext = createContext<ICallContext>(defaultCallContext);
+
+type CallProviderProps = WithChildren & {
+  micOn?: boolean;
+  camOn?: boolean;
+};
+
+export default ({
+  children,
+  micOn: _micOn = defaultCallContext.micOn,
+  camOn: _camOn = defaultCallContext.camOn,
+}: CallProviderProps) => {
+  const [micOn, setMicOn] = useState(_micOn);
+  const [camOn, setCamOn] = useState(_camOn);
+
+  return (
+    <CallContext.Provider
+      value={{
+        micOn,
+        setMicOn,
+        camOn,
+        setCamOn,
+      }}
+    >
+      {children}
+    </CallContext.Provider>
+  );
+};