log output: initial move to DATADUMP

This moves most of the biggest log outputs from DEBUG and INFO to DATADUMP. Turns out, there weren't all that many.

Next I'm reevaluating the log level assigned to each output. Ideally I'm thinking the default log level should be INFO (20) and should give the user a good picture of what their node is doing on the network without being too much or too many to read in realtime.
> Otherwise, any code that uses datadump will fail unless openbazaar_daemon has been previously imported.

Indeed, the unit tests broke when I started adding datadump outputs and it's why I added this commit to relocate the custom log level code. It fixed the unit tests but I hadn't thought about other cases.

For my own benefit, I'm curious what other cases you're thinking of that will fail after this PR? Datadump can be used from anywhere while OB is running and while the tests are running and I'm not sure what other use cases there are.

Regardless, I'll do it like you said. I don't speak Python natively so I'll have to do some research first.