auth: Fix memory leaks in the bind file format parser

auth: Fix memory leaks in the bind file format parser

Some tokens were not properly freed: ACL names and entries, unused
word or quoted string terms. This is limited to the parsing of the
bind file format, zones themselves are fine, so there is no security
impact.
Found by LeakSanitizer over our existing unit tests.

(cherry picked from commit 9a8bd90d2f9beffba267c91b0a9d37aefcc2836e)