FR: Collected loaded XDC files

Collect the loaded XDC files and associate WARNINGs to these XDC files.

```
Processing XDC Constraints
Initializing timing engine
Parsing XDC File [C:/Git/PLC2/Training/StopWatch/project/4_WithTiming.runs/synth_1/dont_touch.xdc]
Finished Parsing XDC File [C:/Git/PLC2/Training/StopWatch/project/4_WithTiming.runs/synth_1/dont_touch.xdc]
Completed Processing XDC Constraints
```