The tasks queue does not have a maximum capacity

Every modification to a document produce a task which stored but also added in a memory queue, and you can sometime have a huge number of those tasks.

For example, I just found in a memory dump (automatically triggered by an OutOfMemory) a 759091 queue which is using about 150MB. While rare in a normal runtime, this can happen with which exceptional activity or simply when reanalyzing all the documents of an instance (which was the use case here, I think).

Since all the tasks are stored, the memory version of it should ideally only be a limited extract of the full queue, serving more as a cache than the reference queue.