package/gerbera: bump to version 1.4.0

Also:
 * Drop patch 0001 (fix static linking of libmagic) applied upstream
 * Add optional dependency on libmatroska
 * Add upstream patch to fix building with libmatroska
 * Adjust spacing in hash file to 2 spaces

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>