High RAM usage during particle creation with MPI #5106
Description
Running the same code using the last stable Espresso version and the current development version, RAM usage on my machine goes from ca. 3gb (stable) to over 16GB (developer). On the developer branch, running the same code without MPI reduces the RAM usage to about 4GB (still notably higher than the latest stable release). I noticed this issue while iteratively creating particles and making some of them virtual, so the cause must be related to these things. Testing was done in a Docker container using images that are basically the same ones as we use for CI.