Unify configuring AET testing throughput

[malaskowski]

Version used

• AET 3.0.0

Context of the feature

Now to properly configure AET testing throughput (number of concurrent tested urls) several different configurations that values are correlated needs to be adjusted:

1. RunnerConfiguration.maxMessagesInCollectorQueue which tells how many collection tasks can be scheduled in the system in one time
2. CollectorMessageListenerImpl configurations, each config entry (this is OSGi config factory) spawns new Collector worker, number of those workers also limits the maximum number of concurrent collect tasks done in the system.
3. Number of browsers in the system (number of Selenium Grid Nodes browsers).

At least configs 1 and 2 should be configurable more intuitively, e.g. there should be one configuration, where user sets the number of browsers that are in the system, or even better, if this is possible, number of browsers should be detected automatically and 1, 2 set automatically.