Add system_id (#18040)

This PR adds `system_id` to telemetry, which is contained within a new
`global` database (accessible by any release channel of Zed on a single
system). This will help us get a more accurate understanding of user
count, instead of relying on `installationd_id`, which is different per
release channel. This doesn't solve the problem of a user with multiple
machines, but it gets us closer.

Release Notes:

- N/A