Optimization trigger component

[jsjason]

Although we are planning to execute optimization periodically, we want to be able to implement other trigger conditions such as waiting for a change in the amount of available resources, or delaying optimization in case more metrics need to be gathered for a valid optimization run. The most flexible design would be having a small component just for triggering optimization, preferably on the same machine as the profiler and optimizer.

Related to #9, which was opened for the BSP dolphin framework.