Migrate from sewing-kit-next to loom

[BPScott]

Description

sewing-kit-next has been renamed to loom, and has been moved into the shopify npm namespace. Code behaviour in the latest packages from the @sewing-kit namespace is identical to the corresponding package in the @shopify namespace aside from the binary name, the config file name and the metadata directory.

This PR:

• Replaces @sewing-kit/core with @shopify/loom, @sewing-kit/cli with @shopify/loom-cli and @sewing-kit/plugin-* with @shopify/loom-plugin-*
• Uses the loom executable instead of skn
• Renames sewing-kit.config.ts to loom.config.ts
• Ignores .loom instead of .sewing-kit in ignore files

Annoyingly git's rename detection gets confused by all the renames of short and practically identical per-package loom.config.ts files :(

To Tophat

Confirm every package has a new loom.config.ts file

ls -1 'packages' | wc -l
      74
ls -1 packages/*/loom.config.ts | wc -l
      74
ls -1 packages/*/sewing-kit.config.ts | wc -l
zsh: no matches found: packages/*/sewing-kit.config.ts
       0

• Checkout the main branch into ~/projects/quilt, Run rm -rf .sewing-kit; git clean -f -x packages/*/build; yarn build to generate a fresh build of main.
• Checkout out this branch into another folder and run rm -rf .sewing-kit; git clean -f -x packages/*/build; yarn build to generate a fresh build of this branch
• Run for PACKAGENAME in $(ls -1 packages) do; diff -ru packages/$PACKAGENAME/build ~/projects/quilt/packages/$PACKAGENAME/build -x '*.tsbuildinfo' to run diffs of every packages's build output.
• Noted that no differences occur aside from a change in type reference load order in react-shortcuts.

Type of change

-All: patch

Build output should be identical

[dahukish]