Change generic provider link to the registry, since the majority of
providers are no longer under the terraform-provider org.
Remove example link to an individual user's repo.
Add a written bug triage process and link to it in README.md
Bug process
Remove goals, edit for brevity, and move how to write a good issue report to bug report template
link HashiCorp GPG key in bug report template
add summary links for triage process
Here our prior existing single template becomes the "Bug report" template,
and we introduce a second "Feature request" template that is more
appropriate for gathering context about a feature request.