Improve NodeInfo cache
When any information in LDAP about node is updated, the whole NodeInfo cache is invalidated - it's not a problem on small instances, or when there are no node properties, but on large systems with a lot of node properties, it can take more than 6 seconds, which locks virtually everything related to nodes.
Other symptoms are:
- LDAP using a lot of CPU,
- LDAP timeout in webapp logs.
- check if there are entries with a newer modification date
- if so, fetch all entries with the newer modification date
- construct the new nodeinfo from these entries, completing with the cache for what's missing
- replacing within the cache the updated entries