Reduce session updates
The session creation process is not optimal and generates in backend at :
- 1 op to create the session with only the _session_id key (Common::Session)
- 1 op to add the _session_kind key (Common::Session)
- 1 op to add the others keys (Portal::Simple::store)
- 1 op to add the _issuerDB (Portal::Simple::issuerForAuthUser)
- If _issuerDB is SAML or OpenID, another op to update _lastSeen.
The goal is to reduce the number of updates. With DBI or LDAP backend, this should give a good performance improvement.