virtualbox: added execution and state modules for VirtualBox Guest Additions installing
virtualbox: removed unused function
virtualbox module: add examples to mount functions
virtualbox module: handle non VirtualBox Guest Additions CD or absence of CD at all
virtualbox module: remame to vbox_guest
vbox_guest module: add functions to manage users that have access to shared folders
vbox_guest module: documentation fixes
vbox_guest module: satisfy pylint
vbox_guest module: documentation fixes
vbox_guest module: addition_install: added support for fedora and ubuntu
Merge pull request #15175 from rominf/virtualbox

 Modules for VirtualBox Guest