Remove C version; clean up build and packaging

- Remove the legacy C code; we're not building for IRIX
  or Solaris anymore.
- Remove the autotools and replace it with a simpler
  Makefile
- Add Python script to generate the sysnames, in preference
  to doing it in debian/rules
- Add debian/source/format and gbp.conf.
- Depend on the necessary OpenAFS version to allow long
  sysname lists (now present in all distros we build for)
- Build-Depend on Python
- Wrap Depends and Build-Depends fields in control file