Instead of having to use grep, this adds the ability to print out only
transactions that update a particular key, or to filter out entirely
keys except those updating certain btrees.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This factors out cmd_kill_btree_node into its own file - it was in
cmd_list_journal.c, which wsa rather silly.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>