* Add Greenfield API endpoints for retrieving app details
* add app items details
* Add GetPosApp and GetCrowdfundApp to LocalBTCPayServerClient
* Simplify POS app data items example
* Document app type enum
* make "RequiresRefundEmail" nullable
* remove "Template" and "PerksTemplate" fields
* Editorconfig: Add space_before_self_closing setting
This was a difference between the way dotnet-format and Rider format code. See https://www.jetbrains.com/help/rider/EditorConfig_Index.html
* Editorconfig: Keep 4 spaces indentation for Swagger JSON files
They are all formatted that way, let's keep it like that.
* Apply dotnet-format, mostly white-space related changes