reorganize debian packages (Closes: #1168)
- Merge cubicweb-core into cubicweb-common
- Fix lintian errors
- Install bash_completion file correctly
- Clean debian/rules
debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/web usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/share/cubicweb/cubes/shared/data usr/share/cubicweb/cubes/shared
debian/tmp/usr/share/cubicweb/cubes/shared/wdoc usr/share/cubicweb/cubes/shared