Fix action/grouping lookup mechanics

When we are following references towards the original definitions
we need to mind the fact that 'uses' statement may point to a grouping
in a different module and hence we need to adjust namespace accordingly.

The same thing applies when we want to find generated types for such
actions' input/output -- here we need to acquire the correct
ModuleContext.

JIRA: MDSAL-516
Change-Id: I1931279beb8e663e6d8558d50c5d7d274e248cf3
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>