devel/libhash: Deprecate and set expiration date to 2021-12-31

Abandoned by upstream in 2006
No users and removed in pretty much all other package repositories
No dependency in FreeBSD ports

Reference:
https://repology.org/project/libhash/versions

PR: 258523
Reported by: diizzy

(cherry picked from commit bcccec1adcc7696fd83881ce0e650e74deacf62d)