Allow to apply project CRDs before an upgrade by adding two variables:

* ``APPLY_PRE_UPGRADE_CRDS``: if set to true, finds all ``yaml`` files in ``crds`` path and applies them just the for an upgrade.
* ``APPLY_PRE_UPGRADE_URL``: if set to a non-empty value, runs ``kubectl apply`` on the content of this variable them just the for an upgrade.
