Upgrade to / support new version lit@2

[thescientist13]

There's an upcoming version of lit-html and lit-element where everything will get consolidated under a new top level lit package.

As part of the upgrade process, it is required to drop the old package name references and change import statements. For this reason, in the Greenwood website project, we will not be able to support evergreen-web-components unless they are also upgraded to use the new lit package.

Hopefully not too much effort, and will try and take a look at making the change myself as the APIs of lit-html and lit-element should be mostly backwards compatible, and so far things we working well in the Greenwood website.

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I assume this would initiate a major version bump, which would seem reasonable to me.

Let me know your thoughts!

[hutchgrant]

This looks like a good idea. I'll look into it soon.

[hutchgrant]

Updated to lit 2.0 all packages. No breaking changes.