[th/uuid] extend internal UUID API
improve libnm-core to expose UUIDs in their binary form. Previously, all API was handling only UUIDs in string form, and at the few places where we needed the binary form, we would include
uuid.h. Note that sometimes we indeed needed the binary form. With this,
uuid.hwill only be required by
libnm-core/nm-utils.c(not yet done, there are still external users. But that can be fixed next).
add support for generating SHA1 based version 5 UUIDs.