* 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
We're keeping the `store-integrations-list` extension point name for backwards compatibility, otherwise I renamed all "integration" occurences in the views and also the routes.
Note: We still refer to external software like WooCommerce, Drupal, Magento and such as "integrations", I think that distinction makes sense.
Closes#3594.