rov-server: Changed dependency to pi-blaster for PWM

Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>
rov-image-sato: Added pi-blaster to image

Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>
rov-server: Added missing boot script

Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>