Convert init.d scripts to use procd and take advantage of respawn
feature.

Signed-off-by: Marcin Jurkowski <marcin1j@gmail.com>

Owfs daemons lack control scripts. This patch adds init.d scripts for owfs,
owserver, owhttpd and owftpd packages.
Most daemon options (both common libow and program-specific parameters)
are reflected as uci config variables.

Signed-off-by: Marcin Jurkowski <marcin1j@gmail.com>