* Allow overrides on all methods
* Add non-returning SendHttpRequest methods
* Use SendHttpRequest consistently
* Use file-scoped namespace
* Rates: Set default null value for currencyPair
* Ensure it works with instances which have BTCPAY_ROOTPATH set
* 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
