Figure out automation of the "all" team on GH about wg HOT 3 OPEN

@BartMassey looking at the toml docs: https://github.com/rust-lang/team/blob/master/docs/toml-schema.md

It appears we could instead:

• remove all people.members of wg-embeded.toml
• add a people.included-teams section, listing all substeams
• add the [[github]] section as proposed above

from wg.

We should also add website.zulip-stream while we are at it.

from wg.

Option 4: Construct the all team as the union of the team manifests in CI. Optionally check to ensure that this matches the [[github]] manifest.

Or is the [[github]] manifest already this?

from wg.