Add support for custom repos in FreeBSD.

ansible/roles/package_manager/templates/custom.conf.j2

@@ -0,0 +1,8 @@
+custom: {
+    # url: "file:///opt/pkgrepo/packages/current-default-framework"
+    url: "https://freebsdpkg.fizz.buzz/repo/{{ custom_repo }}",
+    enabled: yes,
+    signature_type: "pubkey",
+    pubkey: "/usr/local/etc/pkg/poudriere.pub",
+    priority: 100
+}