#20 add beginning of Cloudflare Turnstile support
Quick and dirty implementation of #20 Cloudflare Turnstile support, attempting to re-use settings and such.
Faking a recpatchaVersion of 0 for Cloudflare Turnstile to minimize initial changes. Code should probably be refactored a tiny bit to more cleanly represent multiple types of captcha implementations.
NOTE: Have not touched the Angular and Afform pieces. This seems to work for initial form testing. May need more implementation. Consider this a starting point.
Also added Form Protection Settings options for theme (light or dark) and Turnstile appearance (always, interaction-only, execute).
Future:
- Would be nice to initial verification features similar to what the WordPress Plugin Simple Cloudflare Turnstile does in settings.
- Add test cases perhaps using Cloudflare Turnstile dummy sitekeys and secret keys.
- Add error checking beyond success or not. Server-side error codes.
- Could also consider client-side error codes, if desired.