Greenfield: Rename API key redirect params; switch to POST body (#1898)

* Rename user param to userId in API key redirect

This way it is clearer what to expect and it also make the parameteer easier to consume.

* Post redirect: Allow form url and prettify page

- Form URL as alternative to controller/action for external URLs
- Making it look nice and add explanation for non-JS case

* APIKeys: Minor view updates

fix

* APIKeys: Use POST redirect for confirmation

fix

* UI: Minor update to confirm view

Tidies it up and adapts to the newly added ConfirmAPIKeys view.

* APIKeys: Update delete view

Structures the information in title and description better.

* APIKeys: Distinguish authorize and confirm (reuse)

* Upgrade ChromeDriver

* Test fixes

* Clean up PostRedirect view

By adding missing forgery token

* Re-add tests for callback post values

* Rename key param to apiKey in API key redirect

* Update BTCPayServer/wwwroot/swagger/v1/swagger.template.authorization.json

Co-authored-by: Andrew Camilleri <evilkukka@gmail.com>

* Use DEBUG conditional for postredirect-callback-test route

* Remove unnecessary ChromeDriver references

* Add debug flag

* Remove debug flags

Co-authored-by: Andrew Camilleri <evilkukka@gmail.com>

BTCPayServer/Models/PostRedictViewModel.cs

@@ -6,6 +6,8 @@ namespace BTCPayServer.Models
     {
         public string AspAction { get; set; }
         public string AspController { get; set; }
+        public string FormUrl { get; set; }
+
         public List<KeyValuePair<string, string>> Parameters { get; set; } = new List<KeyValuePair<string, string>>();
     }
 }