TBG: Add Defaults via Env for -s|-t

This feature shortens the tbg call dramatically without harming its generality.

The `-s | --submit` option is the batch system and unique for each machine. That is a perfect candidate for a `picongpu.profile` or a general `.profile` setting (as a default).

The `-t | --tpl` file is useful if you have various queues or debug templates. 99% of the users always submit to the same queue and would need a default, too. Developers or users with varying queues can still use `-t` to overwrite the default.