Add non-minified version of isotope.pkgd.js

[legoktm]

Debian wants to have the source files for minified scripts. Otherwise
same rationale as #368 which was for jquery-ui.

I downloaded this from https://unpkg.com/isotope-layout@3.0.6/dist/isotope.pkgd.js.

[codecov]

Codecov Report

Merging #693 (b94e4b7) into master (6846507) will decrease coverage by 2.83%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #693      +/-   ##
==========================================
- Coverage   60.80%   57.96%   -2.84%     
==========================================
  Files          54       54              
  Lines        3944     3566     -378     
  Branches     2006     2006              
==========================================
- Hits         2398     2067     -331     
+ Misses       1545     1498      -47     
  Partials        1        1              

Impacted Files	Coverage Δ
src/server.cpp	79.16% <0.00%> (-14.78%)	⬇️
src/tools/otherTools.cpp	82.56% <0.00%> (-9.99%)	⬇️
src/tools/pathTools.cpp	49.14% <0.00%> (-8.08%)	⬇️
src/manager.cpp	75.40% <0.00%> (-1.87%)	⬇️
src/server/request_context.cpp	67.39% <0.00%> (-1.69%)	⬇️
src/kiwixserve.cpp	35.48% <0.00%> (-1.66%)	⬇️
src/server/internalServer_catalog_v2.cpp	95.00% <0.00%> (-1.56%)	⬇️
src/server/internalServer.cpp	81.06% <0.00%> (-1.55%)	⬇️
src/tools/archiveTools.cpp	78.26% <0.00%> (-1.45%)	⬇️
src/opds_dumper.cpp	99.07% <0.00%> (-0.93%)	⬇️
... and 17 more

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[veloman-yunkan]

I am not sure what I can review about this PR