[siemens] updated questa.hjson

### Description

Hi,
I'm not yet approved for submitting changes. So here's a questa.hjson that at least compiles.
It should be put in hw/dv/tools/dvsim/questa.hjson

I'm still climbing the learning curve on the scripts - in some cases when you select questa, it'll get *most* of it right, but still use VCS in one place or two.

[questa.tar.gz](questa.tar.gz)

Start with the proposed hw/dv/tools/dvsim/questa.hjson and the attached questa.tar.gz, then inspect the scripts that select Questa and currently fall back to VCS. Done means the configuration compiles and selecting Questa no longer uses VCS in the remaining cases described.

Written by the indexing model from the issue text.