fix: bud install conflicts

[kellymears]

This should absolutely not be merged until after 5.0.0 is released and we have space to do next builds that aren't majorly disruptive to peoples workflows.

Problem

bud's handling of transitive dependencies is insufficient to deal with bud extensions that rely on other extensions (see sage -> wordpress-preset -> react -> babel)

this is the primary cause of issues like #567, #730. actually, installs work fine if you are installing a root level extension (like babel, sass). it is only when installing presets and the like that the problems come to the fore.

Rundown

• if an extensions declares another one as a dependency then they will be registered in that implied order (i think if it is cyclical it ends up being a race and also don't do this)
• if an extension has unmet dependencies it will be marked as invalid and bud won't process its major callbacks
• if an extension has unmet dependencies and is depended on by other extensions all of them are flagged invalid
• unmet dependencies are tracked separately from missing extensions. because they are super stupid different.
  • when you run install it will install all missing extensions, first.
  • then, it rebuilds the project graph
  • then it installs missing dependencies
  • otherwise you might have to run install more than once.. because with each extensions you pull in additional deps. that weren't present during the first run, and it needs to keep doing sets of installs until it reaches bottom. extensions first. deps all at the end.

Changelog

• fix: $ bud install (and other commands) displaying a loading spinner and "compiling" message during run
• improve: more directly utilize bud instance for installation.
• use a graph api to instantiate extensions in an order that is sensitive to extension dependencies
• will skip instantiating/registering/booting extensions which have unmet dependencies

refs: #567, #730

[kellymears]

closed in favor of #886