Use the loglevel library's extensions

...instead of monkey patching the console log objects. We use a logging
framework everywhere now (this fixes the times when we didn't...)
so there's not really a reason to do this the hacky way anymore.

This means that log lines now appear to come from whatever else is
intercepting the logger (eg. sentry) rather than rageshake.ts.

Opinions on this welcome on whether it's better or not.

src/matrix-utils.ts

@@ -177,7 +177,7 @@ export async function initClient(
   try {
     await client.store.startup();
   } catch (error) {
-    console.error(
+    logger.error(
       "Error starting matrix client store. Falling back to memory store.",
       error
     );