introduce `last_commands` variable that can be pulled to see what went wrong with the previously issued command(s)

[sebkopf]

basically list the codes for each component type and the component IDs it covers (variable limited to 1024 characters might be tricky here)

{
	"pump": {
		"ids": ["x", "y", "z"],
		"warnings": [
                     {-11: "blablub", -12: "whatup yeah"}
                  ],
                 "errors": [
                     {13: "blablub", 15: "whatup yeah"}
                  ]
	},
	"alicat_mfc": [],
	"scheduler": []
}

--> more realistic to actually use last_commands to check what happened (and then that can include the error message), basically a copy of the last status changes/messages (however many fit into the 1024 buffer), i.e. a copy of the debug_state info (some of what went into the database/log)