Add webc support

[oscarotero]

Enter your suggestions in details:

Add the webc plugin to use webc components.
Based on https://github.com/dz4k/denizaksimsek.com/blob/master/_build/webc.ts

[JosefJezek]

Do you plan to support for webc? We also need is-land element.

[oscarotero]

There's an initial version here: https://github.com/lumeland/experimental-plugins/tree/main/webc
It needs more work but there's a demo with the basic usage.

is-land element doesn't need a plugin, it's a web component. You only have to import the script and that's all.

[JosefJezek]

We need support for webc:keep. Do you have an idea for implementation with JS and CSS bundler in Lume?

https://github.com/11ty/eleventy-plugin-bundle#use-with-webc