Add links to more tests

[DelayRGC]

Only 6 out of some 260+ tests have links leading to their github repos.
We should add links to more of them. And if they happen to not have a repo, at least link to a download so people can run the tests on their own emus.
The testroms are all in this repo, but going via the webpage should still be possible too.

[Rangi42]

Instead of linking every individual test, we could have a modal dialog or second page or tab that links to the test collections (blargg, acid, mooneye, etc).

Or we could link the collection part of each test's name, e.g. "blargg/cpu_instrs/​01-special.gb".

[DelayRGC]

I think the collection would work best; these tests are (mostly) all parts of suites anyway, so linking to the suite sounds good.
I don't know about a second page though, you already have all the tests right there on the main page anyway.

I feel like there's a way to format the main page to make use of that. Perhaps add separators between each test suite with a link to that suite? Having a huge results matrix isn't particularly readable to begin with.

[Rangi42]

Yeah, separators would be great for skimming down the whole unfiltered table.