Fix dotcom installs, better script/check-versions reporting

[shawnbot]

This does a couple of things to get installations of alpha release working in github/github again:

1. Removes all of the package-specific package-lock.json files (but keeps the top-level one)

2. Removes peerDependencies fields for primer-marketing-buttons and primer-popover, both of which were causing headaches

3. Improves the script/check-versions script:

   • It now recognizes file: version specifiers
   • It reports all of the version mismatches at once, rather than bailing on the first one

These commits are cherry-picked from #573, and I've confirmed that they solve the issues with both CSS builds and licensing checks in github/github when you install it with something like:

pushd ~/primer/primer
primer="$(jq -r .version modules/primer/package.json)"
config="$(jq -r .version tools/stylelint-config-primer/package.json)"
commit="$(git rev-parse --short HEAD)"
popd
bin/npm install \
  "primer@$primer.alpha-$commit" \
  "stylelint-config-primer@$config.alpha-$commit"

[jonrohan]

I can't think of any reason this wouldn't work. Let's try it and fix if we run into problems 👍