build: remove Vagrantfile
build: remove Vagrantfile

This Vagrantfile hasn't been maintained for a long time and no longer
produces a correct and functioning development environment for Terraform.

Terraform's development environment is a pretty standard Go development
environment, so a custom VM setup for development is overkill. Maintaining
the Makefile and other similar dev environment helpers is already overhead
enough, and having this stale Vagrantfile here was occasionally causing
folks to try to use it and get frustrated that it didn't work.

ewbankkit/terraform,heimweh/terraform,pryorda/terraform,heimweh/terraform,brandontosch/terraform,rnaveiras/terraform,hashicorp/terraform,pryorda/terraform,pdecat/terraform,apparentlymart/terraform,VladRassokhin/terraform,ewbankkit/terraform,pdecat/terraform,pradeepbhadani/terraform,nlamirault/terraform,apparentlymart/terraform,tommynsong/terraform,VladRassokhin/terraform,apparentlymart/terraform,tommynsong/terraform,rnaveiras/terraform,VladRassokhin/terraform,heimweh/terraform,heimweh/terraform,brandontosch/terraform,heimweh/terraform,luis-silva/terraform,VladRassokhin/terraform,gechr/terraform,drebes/terraform,nlamirault/terraform,pdecat/terraform,pradeepbhadani/terraform,ewbankkit/terraform,luis-silva/terraform,luis-silva/terraform,hashicorp/terraform,drebes/terraform,ewbankkit/terraform,brandontosch/terraform,nlamirault/terraform,brandontosch/terraform,brandontosch/terraform,drebes/terraform,pradeepbhadani/terraform,tommynsong/terraform,pryorda/terraform,gechr/terraform,drebes/terraform,apparentlymart/terraform,gechr/terraform,luis-silva/terraform,rnaveiras/terraform,hashicorp/terraform,apparentlymart/terraform,pdecat/terraform