Proposal: Create Transformer to add link to original event

[HannesHil]

Considering GDPR and convenience i would like a link to the original event in the source calendar. In this way one only has to open the link for further info instead of searching for it.

I have seen similar links in the debug logs.

[alxndr13]

Closed as this was implemented in #216

[alxndr13]

ah damn, i can't close it anymore 🥲 (for obvious reasons) cc @MichaelEischer @timonegk