ESLint preset and rules

[brainkim]

After seeing some crank code in the wild I definitely think Crank could do with some rules to make writing cranky code a little easier and catch possible bugs.

Some possible rules specific to Crank:

• Warn when a dev provides a default value for a prop in the parameter list which isn’t exactly reflected in the context iteration (nobody discovered this flaw of this iteration in the many issues discussing library design heheheheheh).
• Warn when a dev yields and implicitly returns from a generator component without a loop.
• Warn when a dev unnecessarily uses generator components.
• Warn when a dev unnecessarily uses async components (maybe handled by missing await.

I think we might also want to squash for ({} of this)/for await ({} of this) errors as well as include the generic JSX/accessibility rules from React.