chore, arrange grouping options in rotz-show in a group option

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, implement rotz-show --pair grouping option

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'cmd/show' into next

* cmd/show:
  minor, implement rotz-show --pair grouping option
  chore, arrange grouping options in rotz-show in a group option