added basic logic for "allowArbitraryExtensions" + "declarationMap" I…

[adrianhunter]

This is a basic implementation that would use the new TS 5.0 Feature "allowArbitraryExtensions" + "declarationMaps" to get basic IDE features like autocompletion or go to definition working in "TS to Civet" cases. It's still not really done/ready, but I always had problems with the custom solution from Civet vscode extension. So if someone wants to try that, better build is version from the civet extension that only gets triggered for ".civet" and ".coffee" files.

So still in progress here :)