Update the beaker instructions

This removes some invalid instructions and refers to
voxpupuli-acceptance for complete documentation. This makes it easier to
update in the future without syncing large amounts of text to a lot of
repositories.

Author: ekohl

moduleroot/.github/CONTRIBUTING.md.erb

@@ -232,33 +232,7 @@ simple tests against it after applying the module. You can run this
 with:
 
 ```sh
-bundle exec rake beaker
-```
-
-This will run the tests on the module's default nodeset. You can override the
-nodeset used, e.g.,
-
-```sh
-BEAKER_set=centos-7-x64 bundle exec rake beaker
-```
-
-There are default rake tasks for the various acceptance test modules, e.g.,
-
-```sh
-bundle exec rake beaker:centos-7-x64
-bundle exec rake beaker:ssh:centos-7-x64
-```
-
-If you don't want to have to recreate the virtual machine every time you can
-use `BEAKER_destroy=no` and `BEAKER_provision=no`. On the first run you will at
-least need `BEAKER_provision` set to yes (the default). The Vagrantfile for the
-created virtual machines will be in `.vagrant/beaker_vagrant_files`.
-
-Beaker also supports docker containers. We also use that in our automated CI
-pipeline at [travis-ci](http://travis-ci.org). To use that instead of Vagrant:
-
-```sh
-PUPPET_INSTALL_TYPE=agent BEAKER_IS_PE=no BEAKER_PUPPET_COLLECTION=puppet6 BEAKER_debug=true BEAKER_setfile=debian10-64{hypervisor=docker} BEAKER_destroy=yes bundle exec rake beaker
+BEAKER_setfile=debian10-x64 bundle exec rake beaker
 ```
 
 You can replace the string `debian10` with any common operating system.
@@ -272,11 +246,7 @@ The following strings are known to work:
 * centos7
 * centos8
 
-The easiest way to debug in a docker container is to open a shell:
-
-```sh
-docker exec -it -u root ${container_id_or_name} bash
-```
+For more information and tips & tricks, see [voxpupuli-acceptance's documentation](https://github.com/voxpupuli/voxpupuli-acceptance#running-tests).
 
 The source of this file is in our [modulesync_config](https://github.com/voxpupuli/modulesync_config/blob/master/moduleroot/.github/CONTRIBUTING.md.erb)
 repository.