Add polyfill for text-index compatibility with node 10

[cmdcolin]

This adds a Object.fromEntries polyfill for use in text-index for the CLI

Our CLI currently says it is compatible with node 10.4+ which needs a Object.fromEntries polyfill

xref #2359

We could also bump min to node 12 but this isn't too bad for now

[codecov]

Codecov Report

Merging #2494 (31204eb) into main (78b2adc) will decrease coverage by 0.00%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##             main    #2494      +/-   ##
==========================================
- Coverage   61.18%   61.18%   -0.01%     
==========================================
  Files         543      543              
  Lines       25250    25252       +2     
  Branches     5902     5903       +1     
==========================================
+ Hits        15450    15451       +1     
- Misses       9479     9480       +1     
  Partials      321      321              

Impacted Files	Coverage Δ
products/jbrowse-cli/src/commands/text-index.ts	69.76% <50.00%> (-0.32%)	⬇️

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