revisit log categories
The network and the protocol part of osmo-mgw use the same logging category (DLMGCP). This is a problem because when we want to debug an MGCP protocol issue, we do not want to see all the network/rtp related output. DLMGCP is fine for the MGCP protocol part, but in network we should use a separete category (e.g. DLRTP or DLNET).