Add payment info partial handling

[rainerdema]

Summary

Allow each payment method to define how it is displayed on the confirm and thank-you page.

Checklist

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• [ ] I have written a thorough PR description.
• [ ] I have kept my commits small and atomic.
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[codecov[bot]]

Codecov Report

Merging #334 (402f545) into main (d554de2) will decrease coverage by 0.01%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #334      +/-   ##
==========================================
- Coverage   97.06%   97.05%   -0.01%     
==========================================
  Files         185      190       +5     
  Lines        4494     4484      -10     
==========================================
- Hits         4362     4352      -10     
  Misses        132      132              

Impacted Files	Coverage Δ
templates/app/helpers/checkout_helper.rb	100.00% <100.00%> (ø)
templates/app/views/orders/_payment_info.html.erb	100.00% <100.00%> (ø)
...ates/app/views/orders/payment_info/_check.html.erb	100.00% <100.00%> (ø)
...es/app/views/orders/payment_info/_default.html.erb	100.00% <100.00%> (ø)
...es/app/views/orders/payment_info/_gateway.html.erb	100.00% <100.00%> (ø)
templates/spec/helpers/checkout_helper_spec.rb	100.00% <100.00%> (ø)

... and 2 files with indirect coverage changes

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