Set up tooling to warn/highlight on regressions in package size and dependency graph

[JReinhold]

We need to ensure that new PRs and upcoming work increases our bundle size and dependency graph significantly, now that we've invested so much effort into optimizing and reducing our footprint.

For each PR we want to highlight the following changes, in comparison with the head commit on next:

1. Any changes to individual package's dependencies (including transitive), the total dependency install size (if possible) and the total number of dependencies.
2. Any changes to individual package's devDependencies, that could cause the package's own bundle size to increase, because devDependencies are by default bundled in.
3. Include links to the visual metafile analysis story in our UI Storybook, so that bundle size changes can more easily be inspected.

To reduce the noise, we'll only report these when we detect changes in package's package.json and/or the global lock-file. The global lock-file can impact the prebundled dependencies, so when we detect changes there, we have to compare and highlight all packages.

The report will be sent as a comment by our GitHub bot

Example comment

The following packages have changes to their dependencies:

@storybook/react

	Before	After	Difference
Bundled size	273 kB	300 kB	+28 kB
Dependency count	8	12	+4
Dependency size	3.5 MB	3.8 MB	🚨 +300 kB 🚨
Bundle Size Analyzer	"Link to story on next"	"Link to story on this branch"

@storybook/svelte

	Before	After	Difference
Bundled size	273 kB	200 kB	🎉 -73 kB 🎉
Dependency count	8	12	+4
Dependency size	3.5 MB	1.5 MB	🎉 -2 MB 🎉
Bundle Size Analyzer	"Link to story on next"	"Link to story on this branch"