Sprint 5: PC Builder (Part 2)

What's Changed

• docs: plan milestones by sprint and add build snapshots to the data model by @romulojr-dev in #66
• feat: share a build by link by @romulojr-dev in #67
• feat: fits-your-build hints on product pages and listing cards by @romulojr-dev in #69
• feat: Add to build asks first on a part that doesn't fit by @romulojr-dev in #70
• feat: cart for single items by @romulojr-dev in #71
• feat: add build to cart by @romulojr-dev in #73
• feat: stock flags on the cart page by @romulojr-dev in #75

Full Changelog: v0.4.0...v0.5.0