Bug#962718: split renderdoc qt frontend from non-qt backend

[Eric Anholt <eric@anholt.net>]

Package: renderdoc
Version: 1.7+dfsg-2
Severity: wishlist

When I install renderdoc, it pulls in both the QT GUI for renderdoc
and the renderdoccmd and python renderdoc.so modules.

For resource-constrained systems, it would be nice to be able to avoid
the QT frontend for just replay.  Ustream Mesa CI wants to use
renderdoc traces for correctness testing of drivers, and we build from
source to avoid the QT frontend (some of the test systems bundle the
whole debian and test suites in an initramfs that we try to run on
1-2GB of RAM)  The build is painful to do and slow, and we're close to
our 1 hour build budget for the arm containers already, so a package
of just enough to replay (python backend is what we're using,
renderdoccmd could come with it or not) would be really nice to have.
I would imagine a set of packages like:

- librenderdoc
- renderdoccmd
- python renderdoc.so
- qrenderdoc
- renderdoc (meta package)

but we'd be happy with anything that split qrenderdoc and the qt deps out.

Thanks!