Fix 369 compareAtPrice

[mikemurray]

Resolves #369
Impact: minor
Type: bugfix

Issue

compareAtPrice doesn't display on the PDP page when available

Solution

• Split the ProductDetailInfo info component
• In the new ProductDetailPrice component, add the compareAtPrice display
• Add a compact layout to the ProductDetailPrice that's used for mobile

Breaking changes

ProductDetailInfo has been split into 3 separate components

• ProductDetailPrice
• ProductDetailDescription
• ProductDetailVendor

Testing

Run with the branch from this PR (reactioncommerce/reaction#4731 ) or release-2.0.0-rc.5 or later if it's been merged

1. In Reaction, set the compareAtPrice for a variant and/or variant option
2. On the PDP page for that product, verify the compareAtPrice is displayed. (It's the crossed-out price)
3. On mobile, verify the compareAtPrice is above the price

[mikemurray]

Moved back into WIP. This is missing the compareAtPrice display for the variant option.

[kieckhafer]

Tested against the branch inside reactioncommerce/reaction#4722

Looks good to go once that PR is merged.

[spencern]

@mikemurray @kieckhafer what do we need to do to get this merged?

[kieckhafer]

@spencern just checked it again after the reaction code was merged in. This is good to go, merging now after tests pass.