modelsim ini options for GUI mode

[alexrayne]

modelsim ini options for GUI mode now can setup with via "modelsim.vsim_ini.gui" sim option.

• usage:

simwave = "wave.do"
UI.set_sim_option("modelsim.vsim_ini.gui", { "ShutdownFile": str(simwave.resolve()) });

this provides option in modelsim.ini for GUI-mode simulation:

[vsim]
ShutdownFile=wave.do

That saves all wave-setup on UI close

[alexrayne]

modelsim shutdown do-file saves vsim option, that are overrides vunit one`s.
Now cleanup that options from do-file before run modelsim, so we can use same do-file on multiple test-cases