Add support for translating log levels separately

Use separate message decorating functions for translating log
messages than regular error messages. Each log level uses
its own translation domain, to allow translators to prioritize
translations.

bp log-messages-translation-domain

Change-Id: I05d5c4d019404a07571b1fb101e028e9d9a962a6
Merge "Add support for translating log levels separately"