Use LogService as express log handler

[tadzik]

This makes it as configurable (and as mute-able) as the rest of bot-sdk logs,
instead of always landing on stdout.

Two regressions/changes that this currently brings:

1. Since LogService prefixes every logline with the name of the module that spat it out, this changes the access.log format by prefixing it all with Appservice. Not sure if this is a huge deal since the logs are far too noisy right now to treat them as structured & predictable access logs
2. This adds an extra newline at the end due to both morgan and LogService adding their own