Update the Ember color to the digital version

[MinThaMie]

Discussed with @MelSumner the new Ember color (digitally) is #DB3122 . So we should update that, so we pass the WCAG test (and meet color-contrast Success Criteria).

https://codepen.io/melsumner/pen/JjOmGGr

[MelSumner]

To expand on this a little bit- it's now in our branding guide.

We'll also need to think about how this changes the variations, e.g.,

  --color-brand: #e04e39;  /* this becomes #db3a22 */
  --color-brand-text: #ffd7d2;
  --color-brand-hc-light: #ff5c44;
  --color-brand-hc-dark: #cf2d20;

[MelSumner]

@mansona do you know what the original calculations were for deciding these shades/tints? I'd like to get this shipped so we can get the upgrades into the other apps.

[MelSumner]

Well if we aren't able to get this information, let me see if I can figure out what math was used, so we can get this shipped by EmberConf @MinThaMie