WEBDEV-9446: Move the collection-browser icons into the icons folder

[jbuckner]

Stacked on #177, to dedupe against the earlier sets. Part of WEBDEV-9432. Ported from @internetarchive/collection-browser 4.8.0.

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[github-actions]

PR Preview Action v1.8.1
🚀 View preview at https://internetarchive.github.io/elements/pr/pr-178/
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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.58%. Comparing base (2157453) to head (51b8d79).

Additional details and impacted files

@@                     Coverage Diff                      @@
##           WEBDEV-9443-offshoot-assets     #178   +/-   ##
============================================================
  Coverage                        90.58%   90.58%           
============================================================
  Files                               93       93           
  Lines                             3336     3336           
  Branches                           799      799           
============================================================
  Hits                              3022     3022           
  Misses                             131      131           
  Partials                           183      183           

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