Remove magic() method from context manager

This magic methods brings a lot of issues:
*) Unclear code

*) Recursion and with construction that makes it hard
to understand traces & as well to have a proper workflow

*) Uncontrollable process of creation and deletion of context:
E.g. it's super hard to "abort" creation of context in the middle

*) create() & cleanup() are inseparable => which makes it impossible
to create "persistance context", that have to run separately
setup() & cleanup()

Change-Id: I071c53900441121767ac3550c5ee5790a358ae73