Advanced Serverless Docs

[Zach Leatherman]

Fill in these sections:

https://www.11ty.dev/docs/plugins/serverless/#re-use-build-time-collections

https://www.11ty.dev/docs/plugins/serverless/#swap-to-dynamic-using-the-data-cascade-and-eleventycomputed

[Patrick O'Brien]

@zachleat Do you by chance have examples of https://www.11ty.dev/docs/plugins/serverless/#swap-to-dynamic-using-the-data-cascade-and-eleventycomputed?

I'm looking to explore hooking this up to enable optional auth for all pages in an 11ty site, and I'd be happy to submit an MR to fill in that section once completed if you're looking for assistance.

[Zach Leatherman]

Docs are building