Tweak UI styling

[davkal]

I find the existing UI hard to read. It's good at showing a lot info at high density, but I find that distracting when going through issues (sometimes even via screen sharing). I propose a lighter touch, less dense and more readable.

• keep main color theme based on Vivid and Sharp: https://visme.co/blog/website-color-schemes/
• remove lots of custom styles and embrace Bulma panel and table styles
• updates Bulma from 0.75 to 0.9
• remove datatable-specific styling

Before:

After:

[davkal]

The design is just a straw-person really, I do wonder if others share the issues I'm having. FWIW, I've been using triage party more heavily now, and have gotten used to the existing style.

[tstromberg]

Closing until this can be revisited.