New Metas view, add logo header, new styles, cleanup old cruft

[aminomancer]

I tried disentangling these commits into separate PRs, but it's a bit too complicated, with too many overlapping changes. I think it's best to just merge without squashing, so that each commit is preserved individually in the history.

Features

• Add a Metas view where you can find meta bugs that are not used commonly enough to be included in the sidebar. That way you can probably find a meta for your bug even if you're working on something obscure. This should also help us revive metas that are still relevant, and close metas that are no longer relevant.
• Show a warning color/underline and tooltip on the BMO links for bugs that are missing a meta bug. We have enough metas that all bugs should really have a meta, and it's easier to add them now that we have a Metas view.

Style

• Add a logo header to the top of the sidebar
• Use Mozilla's fonts and typography guidelines (using Google WebFonts, which conveniently has all the Mozilla fonts)
• Fix the broken feature that was supposed to highlight bugs that are assigned to you, and make it stand out more by using a light blue background color instead of slightly bolder type
• Adjust the visual appearance of a few minor elements
• Use the proper ellipsis character instead of three periods
• Adjust priority colors slightly

Fix/Refactor

• Switch to YAML config files where possible
• Change the Issues link on the About page to lead to the proper Issues page, not the "New Issue" page

Cleanup

• Stop tracking non-OMC components (Fixes [FR] Stop tracking non-OMC bugs in Bugzy Triage #289)
• Remove UI for UX/QA needinfos, as the email lists were way out of date and not feasible for us to maintain.
  • I asked around and received an API example for automatically fetching a list of UX designers and QA engineers from people.mozilla.org, based on a list of staff managed by a given manager. However, we can add this later if we think it's important.
• Remove some unused code
• Switch from BugList::render to BugList::children for a few components

[nuggetsnegin]

I'll take a look through this tomorrow morning! 👍🏻

[AllegroFox]

Re: removing the unused components - I remember that the last time I spoke to Scott about it (it was a while ago tbf) the Pocket folks were still actively using Bugzy for triage. I still think we should do this, but it would be nice to reach out and give them a heads up && ask if they're up to maintaining their own fork. I've pinged Scott to see if he knows :)

ETA: We're good!

[AllegroFox]

It's looking good! You addressed everything I noticed on the fly so this is just R+ :)

(we should probably have some tests tho)

[aminomancer]

It's looking good! You addressed everything I noticed on the fly so this is just R+ :)

Thanks!

(we should probably have some tests tho)

Agreed - filed #298