1/ load versioned mdx files from s3 instead of local .versioned_content folder

Summary:
when building static pages, instead of reading from .versioned_content folder, this diff loads versioned content from s3.

next steps:

• versioned images
• update the release pipeline (or update version script) to upload versioned content to s3 instead of checking in to the repo
• remove versioned_content and versioned_images
• update release to skip rc version

Test Plan: preview

Reviewers: sashank, jordansanders

Reviewed By: sashank

Subscribers: jordansanders

Differential Revision: https://dagster.phacility.com/D8415