Support dropping links to zip files

[dtinth]

Changelog

You can now drop a link to a BMS archive (.zip, .rar) from another web page into the “Custom BMS” panel. When you do it, Bemuse will attempt to download and extract the file. Note that for this to work, the web server that serves the file must set up cross-origin resource sharing to allow Bemuse to download it. Both Dropbox and IPFS gateways has this set up already.

Dropbox URL normalization code is based on [@Nekokan]’s Dropbox Replacer, thanks!

[codecov-io]

Codecov Report

Merging #554 into master will decrease coverage by <.01%.
The diff coverage is 50%.

@@            Coverage Diff             @@
##           master     #554      +/-   ##
==========================================
- Coverage   80.86%   80.85%   -0.01%     
==========================================
  Files         156      156              
  Lines        4760     4763       +3     
  Branches      184      184              
==========================================
+ Hits         3849     3851       +2     
- Misses        862      863       +1     
  Partials       49       49

Impacted Files	Coverage Δ
src/app/song-loader/index.js	85.29% <50%> (-1.81%)	⬇️

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