Add NPM workspaces, build using out of the box wp-scripts

[stian-overasen]

I suggest we simplify our build setup by using wp-scripts out of the box, removing the unnecessary entry-files.json setup and introducing NPM workspaces to build all project packages independently (and also from root).

• Introduce NPM workspaces as replacement for entry-files.json system.
• Use out-of-the-box wp-scripts to build theme scripts and stylesheet without additional webpack config.
• Embrace the "Lint globally, build locally" concept:
  • Lint entire project from root.
  • Let each package handle it's own dependencies and build process.
• Add a few additional useful PostCSS extensions. (global data, discard comments)
• Move theme-json generation into dekode-theme and disable script for now since there is no theme-json folder there currently. (This should not be global in case there are additional themes not using this package).
• Add Blueprint plugin as template for fast plugin or block library setup.

A note on entry-files.json:

The entry-files.json autodiscovery script was something we made years ago to support the transition away from Yarn while waiting for workspaces support in NPM. Now that NPM support workspaces (and have for a while) and wp-scripts finally have good support for PostCSS, we don't need the entry-files.json setup anymore. With NPM workspaces we can let each package build itself and at the same time handle dependencies and build everything from root. NPM workspaces can also be combined with e.g. Turbo or wireit to speed up build time with parallelization and caching.

[luistinygod]

@stian-overasen This is a great suggestion and thank you for putting all this together!
While we change this, could we also update the INSTALLATION.md (and/or README.md) files to make sure they are in sync with this new process?
How can we facilitate the transition for our teams? Is there a package blueprint that we could use to start a new plugin that needs a build process and that is compatible with this new workspaces setup?

[luistinygod]

Thank you @stian-overasen!

[github-actions]

Composer package changes

Prod Packages	Operation	Base	Target
dekode/blueprint	New	-	1.0.0
roots/wordpress	Upgraded	6.5.4	6.5.5
roots/wordpress-no-content	Upgraded	6.5.4	6.5.5

[stian-overasen]

INSTALLATION.md updated and blueprint plugin added @luistinygod. This plugin demonstrates building both with view/editor assets and possible blocks.