Port status page to Vue

[Kobzol]

This will make it easier to make changes (e.g. to fix issue #1665). This PR first ports the status page as it was (apart from some tiny code changes, or removing cruft that's no longer relevant, like try commits without a proper date), I will make further changes in follow-up PRs.

To test this, it will probably be easiest to use data from the live server, by changing BASE_URL in site/frontend/urls.ts to this:

const BASE_URL = "https://perf.rust-lang.org/perf";

Then you can open the page locally and on the live server and compare that if it looks the same (it should) :)

[lqd]

To test this, it will probably be easiest to use data from the live server

Yeah agreed, but that also means there was a limit in the number of states I could check: I couldn't easily compare benchmark errors, some states like both "collection in-progress" and "collection complete", the "empty queue" state, missing commits, etc 😓

But it's ok. We'll keep an eye on these rarer states and see if we missed anything then. It should be easy to fix if we can reproduce issues when they happen. The main Status functionality works great, so that's the most important use cases taken care of.