init: more verbose logging

[jmank88]

What does this do / why do we need it?

This proposes some additional verbose logging for init. It fills in some of the downtime before the solver starts logging.

Example output (with fancy diff highlighting I just discovered):

dep init -v
+ Getting direct dependencies...
+ Checked 4407 directories for packages.
+ Found 39 direct dependencies.
Root project is "github.com/treeder/functions"
...

What should your reviewer look out for in this PR?

Better log message/format ideas. Should we consider logging incrementally while scanning the directories as well?

Which issue(s) does this PR fix?

I didn't see an issue for init -v, but #1008 covering status -v is related

[carolynvs]

I think the formatting looks just fine! 👍

If we logged per directory, the verbose output would quickly become too much for any reasonably sized project. Either way I'm really not sure that seeing which directory is being processed for imports would assist troubleshooting. If what we really want is a progress bar or some indicating that dep is "working", let's focus on that instead.