fix: dev: Separate out adbname type flags

There are three adbname flags that are used to identify different
types of adbname lookups when hashing rather than using multiple
hash tables.  Separate these to their own structure element as these
need to be able to be read without locking the adbname structure.

Closes #5404

Merge branch '5404-seperate-out-adbname-type-flags' into 'main'

See merge request isc-projects/bind9!10677