Use animated ID card for doc auth loading interstitial

[aduth]

Why: The Clock icon was used as a temporary asset, and is not intended for use in the final design for this screen. An animation effect was added to the card to give the user the impression there is activity happening in the background, so that they aren't confused into thinking the process has stalled.

Screenshot:

Live Demo:

cc @anniehirshman-gsa

[aduth]

From build failures:

Failures:

  1) SVG files /app/assets/images/id-card.svg does not contain inline style tags (that render poorly in IE due to CSP)
     Failure/Error: expect(doc.css('style')).to be_empty
       expected `[#<Nokogiri::XML::Element:0x2b226ba8e180 name="style" namespace=#<Nokogiri::XML::Namespace:0x2b226ba8...30deg) translate(0, 0) }\n    to { transform: rotate(30deg) translate(260px, -100px) }\n  }\n  ">]>].empty?` to return true, got false
     # ./spec/svg_spec.rb:13:in `block (4 levels) in <top (required)>'

I encountered this in browser testing, where the animation doesn't occur in Internet Explorer. But the card otherwise appears fine:

I was inclined to put this under the category of "progressive enhancement", since the animation is only decorative. The sole purpose of the style tag is to initiate the animation, so it should gracefully degrade.

[aduth]

In f57a865, I add a mechanism to skip style validation for SVG with the explicit addition of a /* test-ignore */ comment.

Why: If there can be a justified reason that the style tag validation should be bypassed, a developer should be able to opt out via explicit override.

I also considered if the pattern should be something along the lines of /* test-ignore reason: ... */, to force the developer to justify their reasoning. I was a bit wary of this, since these files are artifacts that are shipped to users verbatim, and such comments are adding to download size for what should only be relevant for development purposes.

[zachmargolis]

LGTM