Run aggregation

[mj3cheun]

• Refactor of simulation store (cleanup such as addition of missing types)
• Addition of result aggregation (using mean)

[RosaRomeroGomez]

Some high-level comments. They can be addressed in a subsequent PR:

• I think we should show fewer labels on the y axis for each multi-line plot, it looks too crowded.
• I tried around 5 different executions and the mean line gets buried behind the other lines. I think we can either force it to draw it last or set a threshold of 5 executions to start drawing only dots for executions instead of lines.