Redirect user from call page when not in call

When a user tries to access a call page while not in a call, redirect the user to the home page.

Misc changes:

- Add route state to the call route that includes the CallStatus.
- CallProvider redirects to home if the callStatus isn't set (meaning
  the user isn't in a call).
- Remove `beginCall` function in `ConversationProvider`. Added `useStartCall` hook that redirects the user to the call page. The `CallProvider` automatically sends the `BeginCall` message when the user reaches the page for the first time.
- Reorder functions in CallProvider to have `useEffect` functions at the top

GitLab: #164
Change-Id: I6cec1b9f31cb308d92a69112f5b38d1bdf79e05f
diff --git a/client/src/pages/CallInterface.tsx b/client/src/pages/CallInterface.tsx
index c5c0922..b6266ac 100644
--- a/client/src/pages/CallInterface.tsx
+++ b/client/src/pages/CallInterface.tsx
@@ -54,7 +54,7 @@
     return (
       <CallPending
         pending={callRole}
-        caller={callStatus === CallStatus.Ringing ? 'calling' : 'connecting'}
+        caller={callStatus === CallStatus.Connecting ? 'connecting' : 'calling'}
         medium="audio"
       />
     );