Yellow warning indicator lamp of a tringle with an excalmation point in the center and a counterclockwise arrow arround the triangle ---what does it mean?

Check & replace if necessary the brake pedal switch placed above pedals on the support.
If the problem still occurs you might access the ABS & ESP ECU (Electronic Control Unit) using diagnostic equipment connected to the data link connector of the car, in order to pull out all DTC (Diagnostic Trouble Codes) memored.
Then you will be able to replace bad piece(s) and fix the problem by erasing all DTC stocked inside ABS ECU & reset it.

The ESP system means the Electronic Stability Program. If the ESP lights on the dashboard permanently the ESP system is faulty. You must access the ESP Electronic Control Unit (ECU) memory for pull out all DTC (Diagnostic Trouble Codes), using diagnostic equipment connected to the data link connector of the car. Then you will be full informed about bad pieces (e.g.: brake pedal switch, front right wheel abs sensor interrupted, ...). After bad pieces replacement you will be able to erase all faults memored by ESP ECU, in other words reset the ESP system and turn off the warning lamp on dashboard.
I'm convinced that your brake pedal switch is faulty because the glow plug warning sign went ON after ESP warning light. Just replace the brake pedal switch, see if rear stop lamps light when press the brake pedal, and test the car on the road.
Good Luck!