progress: stop using the_repository

Stop using `the_repository` in the "progress" subsystem by passing in a
repository when initializing `struct progress`. Furthermore, store a
pointer to the repository in that struct so that we can pass it to the
trace2 API when logging information.

Adjust callers accordingly by using `the_repository`. While there may be
some callers that have a repository available in their context, this
trivial conversion allows for easier verification and bubbles up the use
of `the_repository` by one level.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/commit-graph.c

@@ -305,6 +305,7 @@ static int graph_write(int argc, const char **argv, const char *prefix,
 		oidset_init(&commits, 0);
 		if (opts.progress)
 			progress = start_delayed_progress(
+				the_repository,
 				_("Collecting commits from input"), 0);
 
 		while (strbuf_getline(&buf, stdin) != EOF) {