Make the `downloadImpl` static method public

I think it's reasonable this stays public as it's not context dependent
and will be useful to write the resource finders.
Start drafting the imgur album resource finder

This also includes a module bootstrapping function for this directory. I
should note that I'm cheating on code coverage enforcement here, since
subdirectories from lib aren't in the blanket `"pattern"` configuration.

I'll add the to it later. This is related to #4.