feat: open Preferences in a new tab

[lidel]

Closes #502

This PR opens Preferences in a new tab, which makes it look the same in every browser.

TODO

• update manifest
• remove vendor-specific quirks and hacks
• improve styling of add-on/src/options/options.css|html
• test styling at various responsive widths for both Chrome and Firefox

---

@jessicaschilling as you suggested in #502 (comment) I've made the backend changes, it works, but needs style work to make it look decent

Shortcuts to build & preview:

• yarn dev-build firefox
• yarn dev-build chromium

[jessicaschilling]

@lidel Thanks! Do you mind reviewing the updated links to documentation so we can get those merged in before I start on this?

[lidel]

@jessicaschilling I've rebased this PR on top of #871 – should be ok to work on this now 👍

[jessicaschilling]

@lidel - FYI, it's getting there in the most recent commit I pushed, but still want to do some more tweaking. It's looking a lot like Web UI prefs now.

[lidel]

Nice! It is already much better!

Small nit: seems color used for .link changed, and that impacts other screens (eg. welcome page).

[jessicaschilling]

@lidel - thanks for the reminder on the welcome screen. There's a few things I'd like to tweak there anyway.

[lidel]

On preferences

I think its already much better than it was and we should merge, but the background color of inputs is bit aggressive:

Perhaps we can use something more subtle? old version used white background and border, here we probably could also use white and color accent on the bottom, perhaps?

On welcome screen

Hm... now those colorful links distract from the content / feel noisy:

Could we move in the other direction, and make links have the same color as text, but make the underline in this color?

For the reference, current master with underline in the same color as text:

[jessicaschilling]

@lidel - made some tweaks as we discussed on Slack. I think this might be ready to go. Had a look around in both FF and Chrome.

I'd like to do something more interesting with the header - like bring the heartbeat cube back in if Companion is active - but that's something for later.

Thanks!

[lidel]

Thanks! Let's...