report: separate common report and per-report args

report: separate common report and per-report args

Separating common report and per-report arguments prepares the code for
handling several reports per one command (for example, the command log
report and LVM command report itself).

Each report can have sort keys, options (fields), list of fields to
compact and selection criteria set individually. Hooks for setting these
per report within one command will be a part of subsequent patches, this
patch only separates new struct single_report_args out of existing
struct report_args.