Add recipe to calculate image size

[imjasonh]

$ crane manifest gcr.io/buildpacks/builder:v1 | jq '.config.size + ([.layers[].size] | add)'
238034322
$ crane manifest gcr.io/buildpacks/builder:v1 | jq '.config.size + ([.layers[].size] | add)' | numfmt --to=iec
228M

[codecov-commenter]

Codecov Report

Merging #1088 (8e9e796) into main (2f6fbf7) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1088   +/-   ##
=======================================
  Coverage   75.46%   75.46%           
=======================================
  Files         107      107           
  Lines        5124     5124           
=======================================
  Hits         3867     3867           
  Misses        709      709           
  Partials      548      548           

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[jonjohnsonjr]

This won't work for an index, how should we handle that?