Simulation Experiment view: should support both our legacy view and (new) UI view

[agarny]

We want our SimulationExperimentView component to actually embed our (current) SimulationExperimentView and SimulationExperimentUiView components. The idea is one or the other to be shown depending on whether:

• there is a JSON UI file associated with OMEX file; and
• the user wants to enforce the use of the legacy view.

IOW:

• if there is a JSON UI file then the user can either see the legacy or the UI view; while
• if there is NO JSON UI file then the user can only see the legacy view.

[agarny]

Fixed by PR #290.