Make "owner" column on index page configurable

This is not really needed for personal sites where all repos belong to
the same person. Since it is pretty useful for shared sites however, it
should be configurable.

Signed-off-by: Florian Pritz <bluewind@xinu.at>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

cgit.h

@@ -203,6 +203,7 @@ struct cgit_config {
 	int enable_filter_overrides;
 	int enable_http_clone;
 	int enable_index_links;
+	int enable_index_owner;
 	int enable_commit_graph;
 	int enable_log_filecount;
 	int enable_log_linecount;