Public room archive

• As a Releng Team Member,
• I want to archive public rooms
• so that:

• test tools like: https://github.com/matrix-org/matrix-public-archive, https://github.com/russelldavies/matrix-archive, ...

Two possible way:

• https://github.com/matrix-org/matrix-public-archive
• https://github.com/matrix-org/matrix-static (interesting for SEO)