ETM should expose their requirements

[MaximeCheramy]

The various ETM require different informations, for instance, the Cache Model needs the SDP, API, etc, the ACET model requires the std dev and the average duration, the fixed penalty requires a preemption cost...

Each ETM should contains a list of parameters that are required, with their type. However, this is not easy as it sounds: sometimes it's a task field or a simulation field, or a processor field, but sometimes it can even be a new kind of data such as the description of the caches.

A first step could be to add several lists of required fields for the tasks, processors and the simulation. This will ease the work on the UI side.