Automatically resolve dependencies if deb file sourced.

 - Uses python-apt module to check for missing dependencies
    and resolve them using apt-get.

 - deb package is then installed in the previous fashion
Mark the missing dependencies as auto-installed.
Fixed a typo in variable name.
lint fixes. thanks jenkins!
Renaming salt.modules.apt to salt.modules.apt_pkg to import python-apt
Updated docstring and added versionchanged for salt.modules.apt_pkg.install
Merge pull request #10161 from tedski/10107

Automatically resolve dependencies when sourcing a deb file.