cmd_seat: split action and config handlers
cmd_seat: split action and config handlers

This separates the logic for seat subcommand handlers that only perform
actions on the seat and handlers that alter the seat config. The former
group can immediately free the seat config after running the command as
it is only used by the subcommand to find the name of the seat to
operate on. The latter group alters the seat config so it will need to
go through the storage and application stage (assuming success).

ascent12/sway,SirCmpwn/sway,1ace/sway,ascent12/sway,1ace/sway,1ace/sway,ascent12/sway