Add method for cache busting requests to the config file in jbrowse-web

[cmdcolin]

We need to look at e.g. a global variable to check this, as there is no configuration file otherwise available to get this from

xref #3045

[cmdcolin]

could also consider enabling by default

[codecov]

Codecov Report

Merging #3381 (61c8ae4) into main (eca394c) will increase coverage by 0.00%.
The diff coverage is 66.66%.

@@           Coverage Diff           @@
##             main    #3381   +/-   ##
=======================================
  Coverage   60.05%   60.05%           
=======================================
  Files         777      777           
  Lines       29418    29420    +2     
  Branches     7117     7118    +1     
=======================================
+ Hits        17667    17669    +2     
  Misses      11560    11560           
  Partials      191      191           

Impacted Files	Coverage Δ
products/jbrowse-web/src/SessionLoader.ts	63.80% <66.66%> (-0.13%)	⬇️
...rative-view/src/ServerSideRenderedBlockContent.tsx	66.66% <0.00%> (+4.16%)	⬆️

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[cmdcolin]

might go ahead and merge