UI layout improvements

[alustig3]

@ThomasAkam I made some changes (hopefully seen as improvements) to the UI. No worries if you disagree and don't merge.

Event trigger

Experiment configuration tab

• made the subjects and variables tables into tabs to give more vertical space as discussed here

Run task tab

• I removed the status because it seemed unnecessary and took up a lot of space. I see how the status can be useful in the experiment view because a lot of information about multiple setups is collapsed/hidden, but in the run task view everything is already in view so the status seems redundant i.e. I never found myself actually looking at the run task status.
• made the top section more compact overall, and user interaction starts in top left and works to the right.

[ThomasAkam]

Thanks @alustig3, these changes all look very nice, I'll merge them now.