Port to GitHub actions & publish to Terraform registry (#39)

* Port to GitHub actions

* Fix

* Make docs terraform registry compatible

docs/data-sources/bitbucketserver_cluster.md

@@ -0,0 +1,29 @@
+# Data Source: bitbucketserver_cluster
+
+Gets information about the nodes that currently make up the Bitbucket cluster.
+
+## Example Usage
+
+```hcl
+data "bitbucketserver_cluster" "main" { }
+
+output "local_hostname" {
+  value = "Bitbucket running on ${data.bitbucketserver_cluster.main.local_node.0.hostname}"
+}
+```
+
+## Attribute Reference
+
+* `local_node` - List with a single element, containing the local node details. See `node` schema below.
+* `nodes` - List of nodes of the Bitbucket cluster.
+* `running` - Flag is the cluster is running.
+
+### Node Schema
+
+Each node in the attributes above contains the following elements:
+
+* `id` - Unique cluster identifier.
+* `name` - Unique cluster identifier.
+* `hostname` - Address hostname of the cluster node. Typically an IP address.
+* `port` - Port of the cluster node. This is not the same as the Bitbucket UI port, rather the node cluster port.
+* `local` - Flag if this is a local node.