Add field for active state

[okwme]

this way we can run collective cron job over github actions to keep checkpoints updated and if the chain is down mark as inactive and skip on subsequent syncs. a user can make a PR to mark it as active if it is back online, once merged it could be part of the cron sync job again.

cron sync job should have a timeout period to mark as inactive

[okwme]

cc @emil-apeunit