feat: standardise icons

[dwmkerr]

This looks good - the icons seem pretty clean. Some issues:

• Labelling instructions might be needed for adaptive icons
• The 'caption' feature of the init command is no longer generating a caption which is readable
• The 'caption' feature of the init command should caption the adaptive icon foreground

[codecov]

Codecov Report

Merging #90 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #90   +/-   ##
=======================================
  Coverage   96.84%   96.84%           
=======================================
  Files          17       17           
  Lines         222      222           
=======================================
  Hits          215      215           
  Misses          7        7

Impacted Files	Coverage Δ
src/init/init.js	100% <ø> (ø)	⬆️

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