dvdrw-tools: new package

The dvd+rw-tools are used to master Blu-ray Disc and DVD Disc media,
both +RW/+R and -RW/-R. Note: The +RW in the name is a historical
artifact. This package contains the widely used growisofs program.

[Thomas:
 - adjust minor formatting issues in Config.in file.
 - remove unneeded empty line in hash file.
 - make the mkisofs symbolic link a relative one.]

Signed-off-by: Steve Kenton <skenton@ou.edu>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>