With this change, the presence of Ansible configuration files (like
playbook file, inventory path, galaxy role file, etc.) is no longer
performed by the `config` classes, but by the `provisioner` classes
(at the beginning of the provision command).
This change fixes several issues:
- Resolve#6984 as `provision` method are only executed when remote
(ssh) communication with the guest machine is possible.
- Resolve#6763 in a better way than 4e451c6 initially did.
- Improve the general provisioner speed since the `config` checks are
actually triggered by many vagrant actions (e.g. `destroy`,...), and
can also be triggered multiple times during a vagrant run (e.g. on
callback request made by the machine provider).
Unlike the former `config`-based checks, the provision action won't
collect all the invalid options, but only report the first invalid
option found and abort the execution.
Some unit tests were not implemented yet to save my scarce "open source
contribution time" for other important issues, but they should be done
at last via GH-6633.
a7ee56459b