Add basic logging and sample upstart btmanagerd.conf

For logging, we print to stdout for now; we will migrate to syslog once
we have the crate.

Start btmanagerd on system start.

Bug: 189501475
Tag: #floss
Test: initctl start btmanagerd
Change-Id: If97c530884ea6c680c187dce7c9edb860e273a0f