Initialise random number generator in Moore, DaVinci

As part of a cleanup of code, see !3680 (merged), we noticed that we are no longer calling the LbAppInit::initRndm function as part of the initialisation of our reconstruction application. This means that we are not setting any seed for random number generators. Random number generators have been used in the past to assign the charge to velo tracks, and some instances of Rndm::Flat are currently present in VPDAQ code related to clusters. In principle, we probably should expect that some random numbers are being used somewhere, in some scenarios.

To make our applications more deterministic, we should make sure we initialise the seed of the random number generator in the initialisation phase of the application. Before this was done by the RecInit algorithm, which no longer runs. It must be guaranteed that this initialisation happens very early in the application. This issue is mostly to identify how we can best implement this.

As it involves PyConf, also @sstahl's input is also much appreciated, and feel free to tag other experts on this matter.