[matter] return exit_st out of matter_main() and main() instead of raising SystemExit
[matter] add --pretend flag, makes possible to run matter in pretend mode directly
[matter] show the list of uninstalled packages at the end of the execution
[matter] fix handling of --pretend in build_args, myopts is not available at that stage
[matter] fix --pretend behaviour. Matter is required to return after dep calculation.
[matter] print particle file name together with particle execution status