Implement using a single system for a simulation

[jd-lara]

With the new capabilities for time series handling we can refactor some of the time series accessing code to enable passing a single system with all the combined time series and avoid users having to employ multiple systems.

[daniel-thom]

The primary aspect of this work to is ensure that PSI can retrieve time series by passing the desired resolution. The current interfaces only support time series type, name, and features. It is possible that we can use features for this, but it might be better to add resolution as a first-class parameter throughout the stack.