Arcyd: refactor, inject mail_sender

Move construction of the mail_sender up and out to where we have access
to the options for arcyd. This so that we're not relying on the
arcyd_reporter to store these options and it can be later removed.

Test Plan:
$ ./precommit.sh
WIP: Arcyd: BREAK, remove arcyd and repo reporters

Prior to moving to a multi-process model, start removing functionality
that won't fit cleanly into the new model.

Remove the 'arcydreporter' and 'reporeporter' code paths.

This breaks the following features:
- logging to the io log file
- logging error messages to the external error logger
- logging some performance stats
- logging general arcyd and repo status

Test Plan:
$ ./precommit.sh
$ git grep -l statushtml
$ git grep -l status-html