Eucalyptus.1 to Eucalyptus.2 upgrade helper functions

Created by: e-kolpakov

This PR refactors helper functions used for Eucalyptus.1 into a class and adds a helper class to perform Eucalyptus.1 to Eucalyptus.2 upgrade.

Author concerns:

As mentioned in https://github.com/open-craft/opencraft/pull/132#issuecomment-244039683, this file was intended as a one-time upgrade helper and should be removed after upgrades are done (which is now the case). We might want to consider extracting them into a some kind of "migrator" package, but it is not clear how it should be structured - most of the migrations will still be a one-time code; we might want to keep them for historical reasons, or remove gradually.