Rework the way transit provider AID masks are built and sent to the RDE.

Rework the way transit provider AID masks are built and sent to the RDE.
ASPA provider AS sets can include optional limitations to inet/inet6 these
limits are represented in the TAS_AID bit masks (2bits per AS).
Introduce a TAS_AID_SIZE() makro that returns the size in bytes of this
bit mask (rounded to the next uint32_t).
Without this change aspa objects with AID specific elements trigger a
fatal error condition when the config is loaded.
OK tb@ job@