Add page listing all demo forms

[MartijnR]

Alternatively, add more demo forms to enketo.org/#samples

[fishbaugher]

Thanks for opening the issue Martijn. I am a fairly experienced developer and was a bit frustrated not to find some central web page listing the various sample/public forms demonstrating various features and issues. There are quite a few out there it seems at places like:

https://enke.to/::grid
https://enke.to/::widgets

but it would be nice to see some other samples around the topics of various way to group and repeat. I suspect they are out there, but just not linked at:

https://enketo.org/#samples