The ephemeral manager keep the inactive ephemeral peers in a linked list. The manager schedule a cleanup procedure to the head of the linked list (to the most deprecated peer). At the end of cleanup schedule the next cleanup to the new head.
If a device connect back to the server the manager will remote it from the peers list.
This PR adds system activity tracking.
The management service records events like
add/remove peer, group, rule, route, etc.
The activity events are stored in the SQLite event store
and can be queried by the HTTP API.
Add a usage_limit parameter to the API.
This limits the number of times a setup key
can be used.
usage_limit == 0 indicates the the usage is inlimited.
