fix grammar in Config_example.txt

Here I tried to fix English grammar in Config_example.txt.

As I didn't understand why some comments start with '#' and others with '##' I changed them all to single sharp sign (except "DANGER ZONE").

Also, as some comments ended with a fullstop and others didn't I put fullstops everywhere.

Where meaning was unclear (see comment about allowBePublic) I tried to elaborate.

Not sure if I understood this comment:
## Transport ID (Controls all)
correctly (the "controlls all" part). Check it please.