[Tech-debt] Get rid-off task serialisers that produces new tasks

[Bulat Gaifullin]

Need to remove old tasks serialisers that produces the several new tasks from one task template.
for example : upload_configuration. this task can be replaced by skipped task and openstack configuration can be moved to astute.yaml (for environment 8.0)

task upload plugin repos and sync plugin tasks also should not produce new tasks also.

This will allow to use lcm.TransactionSerializer in 8.0

[Bulat Gaifullin (bulat.gaifullin)]

this bug about removing a lot of legacy code, that needs to support old environments.
If we add several puppet tasks for old releases during maintenance update, we can remove a lot of legacy code from nailgun.
Aslo we can emulate granular deployment engine through task based engine. only need to add an additional synchronisation points.

To fix this bug need to add next tasks for old releases:
upload_configuration - sync openstack configs to hiera. Need to check, this task can be removed in case if openstack config will be included to astute.yaml

sync plugin repositories, we can include plugins data to astute.yaml and we need a task, that will be create a needed repositories and synchronise plugin scripts into each node.

create vms - need to move check, it is needed to create vm or not into puppet, instead of doing this check on nailgun side.

[Dmitry Pyzhov (dpyzhov)]

Technical debt, doesn't affect real users. Removing from Mitaka release.