New language and page.render hooks#419

I think there should be more hooks to be able to extend and flex an application further. For example case; adding a small process between process layers instead of writing a stand-alone plugin or component for a small process.

For examples:

• template.render:before|after
• page.visit:before|after
• language.create:before|after
• language.update:before|after
• language.delete:before|after
• cache.pages.flush:after

Please add any useful hooks that come to your mind under this idea.

full ack!

With hooks, we might be able to avoid conflicts when extending components, since one plugin takes precedence while all others fail.

Also see hooks before and after blocks are rendered: https://kirby.nolt.io/340

Cache clear hook: https://forum.getkirby.com/t/cache-clear-hook/15999

Language hooks:
https://kirby.nolt.io/67

Great to hear this feature is finally making it .. shoutout and big thanks!