Events: Restore local event time

[iandunn]

Fixes #1170

This changes back to displaying the event date/times in JS, so they can be converted to the visitor's local time instead of being in UTC.

[iandunn]

This is mostly working, just needs some clean up. The one big problem left is that the block fails to render in the template editor. I think it's a similar problem to WordPress/wporg-mu-plugins#500

It's a dynamic block, and the PHP render() passes some data to JS via wp_add_inline_script(). That works well on the front end, but in the editor the JS variable is undefined. Edit() uses <ServerSideRender>.

I guess the "correct" way to do it would be to fork view.js into edit.js as a React component, but it doesn't seem like that should be necessary. It'd waste time and introduce tech debt.

@renintw @adamwoodnz @StevenDufresne, do you have any thoughts on a way to reuse view.js in the template editor, or is the only way to fork it?

[iandunn]

I removed view.js from editorScript since it wasn't working, and added an early return if the global isn't defined. That avoids the explicit error in the editor, but doesn't fix the underlying problem. We can fix that in a future PR if any of you have ideas on that, though.