Use duration type for all duration parameter values

In all cases where duration configuration parameters are used, the type of the corresponding parameter declaration should be MXS_MODULE_PARAM_DURATION.

$ grep -r 'second' *|cut -f 1 -d ':'|sort|uniq
Changelog.md
Filters/Cache.md
Filters/CCRFilter.md
Filters/Database-Firewall-Filter.md
Filters/Luafilter.md
Filters/Throttle.md
Filters/Top-N-Filter.md
Filters/Transaction-Performance-Monitoring-Filter.md
Getting-Started/Configuration-Guide.md
Monitors/Aurora-Monitor.md
Monitors/MariaDB-Monitor.md
Monitors/Monitor-Common.md
Reference/MaxAdmin.md
Reference/MaxCtrl.md
Reference/Module-Commands.md
Release-Notes/MaxScale-2.3.0-Release-Notes.md
Release-Notes/MaxScale-2.3.1-Release-Notes.md
Release-Notes/MaxScale-2.3.2-Release-Notes.md
REST-API/Resources-MaxScale.md
Routers/Avrorouter.md
Routers/Binlogrouter.md
Routers/ReadWriteSplit.md
Routers/SchemaRouter.md
Tutorials/Administration-Tutorial.md
Tutorials/Avrorouter-Tutorial.md
Tutorials/Configuring-Galera-Monitor.md
Tutorials/Configuring-MariaDB-Monitor.md
Tutorials/Encrypting-Passwords.md
Tutorials/Filter-Tutorial.md
Tutorials/MariaDB-Monitor-Failover.md
Tutorials/MaxScale-Failover-with-Keepalived-and-MaxCtrl.md
Tutorials/MySQL-Cluster-Setup.md
Tutorials/RabbitMQ-And-Tee-Archiving.md
Tutorials/Replication-Proxy-Binlog-Router-Tutorial.md