scsictl shall accept generic key/value pairs for options that take parameters

[uweseimet]

Some scsictl options expect more than one parameters for some options, e.g. the options for copying/renaming files. With #1238 there are up to three parameters. The current syntax for such a case expects the parameters in a particular order, separated by a colon. keys are implicit, only the values are specified. If only the third parameter is needed the parameter list has to start with two colons in order to pass the empty parameters, e.g.

>scsictl -s::mapping_info

Sometimes it may be simpler to just pass all possible parameters as key value pairs and in any order, e.g.

>scsictl -soperations=mapping_info:folder_pattern=pattern

In order to support both styles, when there is an equals ('=') character in the parameter list scsictl shall assume that the key/value format is used and parse the parameter list accordlingly.

[uweseimet]

>scsictl -soperations=mapping_info
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