Create get_gpos module, implement get-folder command, and add some module helper functions

[Marshall-Hallenbeck]

I was initially going to have the get_gpos module have the ability to download all of them, hence the helper functions, but LDAP can only query certain GPO information, so it'd have to be another SMB module to download them all; however, the user can just take the GUID output from the module and pass it to --get-folder

get_gpos module:

--get-folder feature: