Remove some polyfills

[AaronDewes]

This should reduce the runtime size & load times somewhat by removing polyfills for older browsers which are not used much.
These browsers include the non-chromium Edge and some older versions of Chrome & Firefox.

In addition, it also updates eslint

[timvisee]

Very nice work once again! I glanced through it, and it LGTM.

I'll try to go through this in full and merge this later today.

[timvisee]

This appears to break the crypto check.

This is in Firefox on macOS:

[timvisee]

crypto.subtle appears to be missing. I guess a polyfill is required for that.

I accidentally merged in error. I may revert this on master if we can't quickly solve this.

[AaronDewes]

crypto.subtle is only available on HTTPS sites and localhost, which is what is causing this. But I'll re-add the polyfill if you develop on other HTTP domains

[timvisee]

crypto.subtle is only available on HTTPS sites and localhost, which is what is causing this.

That makes a lot of sense.

[timvisee]

I have reverted these changes for the time being (in c624766...4ceac20) because it is causing issues for users.

Thanks a lot for your work on this though!

I'd be very happy to put this back in once we get #102 resolved.