ref-filter: implement '--contains' option

ref-filter: implement '--contains' option

'tag -l' and 'branch -l' have two different ways of finding
out if a certain ref contains a commit. Implement both these
methods in ref-filter and give the caller of ref-filter API
the option to pick which implementation to be used.

'branch -l' uses 'is_descendant_of()' from commit.c which is
left as the default implementation to be used.

'tag -l' uses a more specific algorithm since ffc4b80. This
implementation is used whenever the 'with_commit_tag_algo' bit
is set in 'struct ref_filter'.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>