remove unmanaged nodesets

[3flex]

Remove all nodesets which aren't managed in voxpupuli's modulesync_config (https://github.com/voxpupuli/modulesync_config/tree/master/moduleroot/spec/acceptance/nodesets)

This means all will be updated automatically going forward.

Note that until a default.yml is added to modulesync_config, users running acceptance tests will have to specify a nodeset using BEAKER_set= e.g. BEAKER_set=ubuntu-server-1204-x64 bundle exec rake beaker

[3flex]

To avoid issues with missing default.yml it might be preferred to wait until voxpupuli/modulesync_config#229 or something like it is merged, and wait for the next module sync.

But given the acceptance tests haven't been run at all for many months at least, impact of merging before that happens will be minimal.

[dhoppe]

We should also remove default.yml, because this file is not managed via module_sync and the user should be able to choose the operating system as he likes. You can not provide Ubuntu as default, if the user prefers CentOS or anything else.

[3flex]

@dhoppe since I did removedefault.yml from this repo in this PR, can we merge?