Accept both: session name and key parameters

Monitoring of PGSQL over TLS encrypted connection by Zabbix agent2 is possible only by moving all parameters to agent2 side(configuration file). Including DBName, which makes it impossible to use discovery in monitoring.

zabbix_agent2 -t "pgsql.db.size[namedsession,,,postgres]"
pgsql.db.size[namedsession,,,postgres]               [m|ZBX_NOTSUPPORTED] [Invalid parameters: fourth parameter "Database" cannot be passed along with session.] 

Expected:

• Key parameters should be accepted after the (session name|URI).
• Key parameters should override agent conf settings.