Adds initial basic support for HCP based configuration in vagrant-go.
The initalization process has been updated to remove Vagrantfile parsing
from the client, moving it to the runner using init jobs for the basis
and the project (if there is one). Detection is done on the file based
on extension for Ruby based parsing or HCP based parsing.
Current HCP parsing is extremely simple and currently just a base to
build off. Config components will be able to implement an `Init`
function to handle receiving configuration data from a non-native source
file. This will be extended to include a default approach for injecting
defined data in the future.
Some cleanup was done in the state around validations. Some logging
adjustments were applied on the Ruby side for better behavior
consistency.
VirtualBox provider now caches locale detection to prevent multiple
checks every time the driver is initialized.
This uses the new Push plugin support added to the plugin SDK in https://github.com/hashicorp/vagrant-plugin-sdk/pull/106 to make the following changes:
* The plugin manager on the Go side now registers push plugins
* The the _remote_ plugin manager on the Ruby side now calls over to
the go side to get push plugins
* All the wiring is hooked up such that when a push plugin is replaced
with its remote GRPC-client-wielding equivalent, the messages are
ferried around.
