Optionally permanently add to offline list

[JimHeaney]

Currently, offline lists are meant for temporary operation when the network is down. In some applications, we may want some IDs to permanently be on the list. We should add the ability to make non-expiring IDs on the offline list.

[JimHeaney]

Offline list code has been updated to make it so you can set the duration on the list, so we can just set expiration in 1000 years and be OK.