astro/run_oskar.py: change --chunk-size to --max-chunk; to save mem
astro/run_oskar.py: change --chunk-size to --max-chunk; to save mem

Set the maximum allowed chunk size instead of a fixed chunk size.  When the
number of input source number is less than the specified maximum chunk size,
then just use the source number as the simulation chunk size.

liweitianux/atoolbox,liweitianux/atoolbox,liweitianux/atoolbox,liweitianux/atoolbox,liweitianux/atoolbox,liweitianux/atoolbox