builtin: use builtin.h for all builtin commands

builtin: use builtin.h for all builtin commands

Change the builtin/*.c files and wt-status.c files which weren't using
builtin.h to use it, also remove any git-compat-util.h, strbuf.h and
cache.h from those files. We can trust on builtin.h including them.

builtin.h also includes commit.h and notes.h. But I haven't removed
these includes. They're redundant now, but we may want to remove them
from builtin.h in the future.

This impeded my efforts to gettextize git, since I'd otherwise have to
add gettext.h to all of these. Using builtin.h is a good idea in any
case, since it's defining the prototypes for the cmd_* functions that
these files define.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>