Reorganize docker-plugin for consistency

Package and Module names shouldn't have dashes in them, since it makes
it harder to import them (i.e. one cannot use ``import dashed-module``).

Also, moving docker resource under resources for consistency.

Partial-Bug: #1271226
Change-Id: I785b626a99516ebe6444296cf62a78dd96355060
Merge "Reorganize docker-plugin for consistency"