assets: Don't log asset names
Improve logging in development

This commit reduces the verbosity of logging in development, and
standardises the log format so there's only one place to update it.

Many of these changes were made to production.ini in 39046680a, but were
never ported to development.ini.
Include logger name in log format
Merge pull request #1696 from hypothesis/terser-logging

Terser logging