v4l2grab: new package

[Thomas:
 - remove dependency on musl, since libv4l can now be built without
   musl
 - add missing Config.in comment for the toolchain dependencies
 - add hash file.
 - rework commit log.
 - expand Config.in help text.
 - depend on jpeg and not libjpeg, as noticed by Arnout.
 - fix LICENCE_FILE -> LICENSE_FILES typo.]

Signed-off-by: Viacheslav Volkov <sv99@inbox.ru>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>