Extend the Terraform Bitbucket provider to cover most of the API

The existing Bitbucket provider for Terraform (https://www.terraform.io/docs/providers/bitbucket/index.html) does only support three resources:

• repositories
• web hooks
• default reviewers

In order to manage a larger Bitbucket account with Terraform, the provider needs to be extended. Missing resources are:

• branch restrictions
• teams (members, projects, permissions, ...)
• user members
• pipelines / pipeline configs