Use single-request-reopen for Vagrant networking

Fix bug 1035484
Remove Vagrant symlinks options

VirtualBox supports symlink creation since 4.0:
https://www.virtualbox.org/manual/ch04.html#sharedfolders
Change Vagrant share_folder to synced_folder

Removes the NFS option, which doesn't need to be used.
Remove vagrantconfig yaml files and usage
Remove Puppet debugging option from Vagrantfile
Remove gui boot_mode config option from Vagrant
Move is_jenkins check to top of Vagrantfile
Remove support for Vagrantfile config version 1.

Defaults the memory to 512.
Update Vagrant documentation on src dir change
Revert "Remove Puppet debugging option from Vagrantfile"

This reverts commit b778889aab3cd651adb49238da7bff40a2eeca80.
Add Puppet debugging option back to Vagrantfile
Merge pull request #2224 from bramwelt/fix-bug-1035484-slow-vagrant-2

Numerous Vagrant improvements