firmware-utils: new package replacing otrx

firmware-utils: new package replacing otrx

Some of firmware utils may be required on target devices. It's useful
e.g. for dealing with some firmware formats. That is often required
(supporting specific format) to provide an option to revert to original
firmware.

So far we had packaged "otrx" util only for use on Broadcom targets.
Refactor that to package the whole firmware-utils project so we can
package any single util needed.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>