instead of using wsgi, we now use "application" - this tells gunicorn
to look inside the python module application (application.py) for a
wsgi app - and by default that is also called application so rename
the variable.
Also, when running tasks, we're not using gunicorn so need to set the
flask variable in the manifest so that `flask command ...` finds the
app properly.
Remove server_commands as it's not used any more.
specifically, all of the performance platform specific data layout now
happens in performance_platform_client.py - stuff like setting the
_timestamp, period etc, and the perf platform-specific nomenclature is
all handled there.
