Add optional GraphQL endpoint

[jczuchnowski]

Use Caliban

[vpavkin]

I just wonder how often this will end up useful. My guess is that for most of the users it would be just a file(s) they'd have to remove, because they don't need GraphQL.

Maybe it's better to implement it as a separate template 🤔

[vpavkin]

Will investigate an option with an interactive parameter that will add a caliban endpoint