This adds some improvements to `spack find` output when in environments based
around some thoughts about what users want to know when they're in an env.
If you're working in an enviroment, you mostly care about:
* What are the roots
* Which ones are installed / not installed
* What's been added that still needs to be concretized
So, this PR adds a couple tweaks to display that information more clearly:
- [x] We now display install status next to every root. You can easily see
which are installed and which aren't.
- [x] When you run `spack find -l` in an env, the roots now show their concrete
hash (if they've been concretized). They previously would show `-------`
(b/c the root spec itself is abstract), but showing the concretized root's
hash is a lot more useful.
- [x] Newly added/unconcretized specs still show `-------`, which now makes more
sense, b/c they are not concretized.
- [x] There is a new option, `-r` / `--only-roots` to *only* show env roots if
you don't want to look at all the installed specs.
- [x] Roots in the installed spec list are now highlighted as bold. This is
actually an old feature from the first env implementation , but various
refactors had disabled it inadvertently.
eefe0b2eec