Ability to limit particles output

[blendersamsonov]

In simulations where particles multiply a lot, outputting a fixed portion of all the particles can lead to very long write to disk. I propose to add ability to specify maximum number of particles to output via a new parameter in config. In that case I can still, for example, output only each 10th particle, unless they reach this maximum, or by specifying enthp = 1 and maximum number of particles output exactly that many particles.
Implementation seems to be quite straight-forward