SERVER_INFO operation shall accept an optional operation list

[uweseimet]

Protobuf interface clients shall be able to request only a subset of the data returned by the SERVER_INFO command. This command shall be extended to accept an optional case insensitive comma-separated list of operations to return data for, e.g. "version_info,log_level_info". This reduces the transferred data volume in case not all data are needed by a client.
When no list is passed all data are returned, just like before.

[uweseimet]

>scsictl -s::version_info,mapping_info
piscsi server version: 23.10 (development version)
Supported image file extension to device type mappings:
  hd1->SCHD
  hda->SCHD
  hdi->SCHD
  hdn->SCHD
  hdr->SCRM
  hds->SCHD
  is1->SCCD
  iso->SCCD
  mos->SCMO
  nhd->SCHD