Show recent elections in intern command center

Not sure if I'd merge this just yet:
The HTML for this PR is taken straight out of organization.html.
I wanted to use templates to reduce duplication, but I'm not sure how the template system works in this app (in particular why is there views/command-center.html as well as views/intern/command-center.html?)

Also, I wasn't sure which elections count as upcoming/recent. In this case, I'm filtering out all elections that have already ended (i.e. only ongoing and finished will show up). Is this the intended behavior?