* 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
The CoinGecko rate provider is similar to the bitcoin average one, in that you can ask it for a rate from its aggregated sourcing or you can get rates from specific exchanges. I've added support for both.
I haven't integrated it or replaced coinaverage just to see if we should use it as the default and switch everyone to it or what other action to take.
