adds QRcode Interface/Zoid Component functionality

[BriceShatzer]

Adds the zoid component & interface portion of the QRCode UI component being added to SPB here:
https://github.com/paypal/paypal-smart-payment-buttons/pull/158

[codecov]

Codecov Report

Merging #1632 (4c5c3c4) into master (4885982) will increase coverage by 1.96%.
The diff coverage is 20.00%.

@@            Coverage Diff             @@
##           master    #1632      +/-   ##
==========================================
+ Coverage   48.51%   50.48%   +1.96%     
==========================================
  Files          85       90       +5     
  Lines        1076     1143      +67     
  Branches      166      168       +2     
==========================================
+ Hits          522      577      +55     
- Misses        491      505      +14     
+ Partials       63       61       -2     

Impacted Files	Coverage Δ
src/zoid/qr-code/component.jsx	13.04% <13.04%> (ø)
src/interface/button.js	96.55% <100.00%> (+0.25%)	⬆️
src/zoid/buttons/component.jsx	83.07% <0.00%> (ø)
src/zoid/fields/container.jsx	77.27% <0.00%> (ø)
src/zoid/fields/prerender.jsx	100.00% <0.00%> (ø)
src/interface/fields.js	100.00% <0.00%> (ø)
src/zoid/fields/component.jsx	100.00% <0.00%> (ø)
src/ui/buttons/props.js	76.19% <0.00%> (+0.80%)	⬆️
src/funding/funding.js	72.72% <0.00%> (+2.27%)	⬆️
... and 7 more

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[mstuart]

👍

[bluepnume]

LGTM!