For several basic sessions that core provides default ram quota values
exist in the form of enum values. They are used e.g. by init to deduce
session costs. Unfortunately they were not used when actually establishing
the session, which lead to inconsistencies.
Ref #1443
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082
