Generic possibility to pause/resume addon activity for step events

[dvojtise]

On many addons, their behavior may have a significant impact on the execution speed.

This is the case for example for the trace addon or the Sirius animation which significantly slow down the execution speed when activated.

Currently, we can only enable/disable the addon in the launch configuration. Once enabled the addon will proceed during all the execution.

It would be interesting to have a general way to indicate to the addons that they should start/pause/resume their activity.
So we could start full speed up to a point (or breakpoint) then enable the debug analysis using the addons, and disable them once not required anymore.

This pause/resume would mainly apply to the engine events that occurs frequently such as aboutToSelectStep, proposedStepsChanged, stepSelected, aboutToExecuteStep, stepExecuted