Add support for Metricbeat data

[cdahlqvist]

We should add support for simulating Metricbeat data to the track. This will make it possible to simulate mixed workloads from within a single track.

A good starting point would be to support simulation of data and dashboards related to parts of the System Module. This can later be expanded if needed.

• Parameter sources/runners to manage Metricbeat indices with correct mappings and structure.
• Data generating parameter source able to generate infinite amounts of Metricbeat data for a configurable number of simulated hosts.
• Parameter source able to simulate existing default Kibana dashboards with varying and configurable levels of filtering and time periods.
• Create challenges that simulate a number of common scenarios.