conn: Move connection bandwidth stuff into its own file
In connection.c, we have the connection's bw management which means there are lots of functions only dealing with the global_bucket and per-connection rw bucket.
We could move all this to its own file like connection_bw.c to offload connection.c making it nicer, clearer and more modularized.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information