IE/Edge browser compatibility features

[JackMorganNZ]

• Update details polyfill to 2.0.0
• Increase contrast of details elements
  This is done for two reasons:
  • In IE/Edge browsers currently, the border is not shown therefore the background of the detail element should stand out from the page body.
  • Increased contrast for those with disabilities.
• Fix for displaying images correcting in Internet Explorer
• Add CSS styling to display detail elements better on IE/Edge

[codecov]

Codecov Report

Merging #824 into develop will increase coverage by <.01%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #824      +/-   ##
===========================================
+ Coverage    99.53%   99.54%   +<.01%     
===========================================
  Files          102      104       +2     
  Lines         3258     3272      +14     
  Branches       386      386              
===========================================
+ Hits          3243     3257      +14     
  Misses           7        7              
  Partials         8        8

Impacted Files	Coverage Δ
csunplugged/classic/views.py	100% <0%> (ø)
csunplugged/classic/urls.py	100% <0%> (ø)

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[hayleycodes]

I am on a mac with no access to a windows machine at the moment. I have tested to make sure the panels still work as expected on my usual environment, but because I can't see for myself the result on Edge, hesitant to approve this PR...maybe post a screenshot of the result in Edge to convince me?

[JackMorganNZ]

This is what is looked like before PR (IE left, Edge right):

This is what is looked like after PR (IE left, Edge right):