Originally if you had `x -> y -> z`, and an env with `x` in its speclist that is concretized but not installed, then `spack find -c y` would not show anything. This was intended: `spack find` has up-until-now only ever listed out installed specs (and `-c` was for adding a preamble section about roots).
This changes `spack find` so:
* `-c` makes it search through all concretized specs in the env (in a sense it is anticipated that a concretized environment would serve as a "speculative" DB and users may want to query it like they query the DB outside of envs)
* Adds a `-i/--install-status` option, equivalent to `-I` from `spack spec`
* Shows install status for either `-c` or `-i`
* As a side effect to prior point, `spack find -i` can now distinguish different installation states (upstream/external)
Examples:
```
$ spack find -r
==> In environment findtest
==> 1 root specs
- raja
==> 6 installed packages (not shown)
==> 12 concretized packages to be installed (not shown)
```
```
$ spack find
==> In environment findtest
==> 1 root specs
- raja
-- darwin-ventura-m1 / apple-clang@14.0.3 -----------------------
berkeley-db@18.1.40 bzip2@1.0.8 diffutils@3.10 gmake@4.4.1 gnuconfig@2022-09-17 libiconv@1.17
==> 6 installed packages
==> 12 concretized packages to be installed (show with `spack find -c`)
```
```
$ spack find -c
==> In environment findtest
==> 1 root specs
- raja
-- darwin-ventura-m1 / apple-clang@14.0.3 -----------------------
[+] berkeley-db@18.1.40 [+] bzip2@1.0.8 - cmake@3.29.4 [+] diffutils@3.10 [+] gmake@4.4.1 [+] libiconv@1.17 - nghttp2@1.62.0 - pkgconf@2.2.0 - readline@8.2
- blt@0.6.2 - camp@2024.02.1 - curl@8.7.1 - gdbm@1.23 [+] gnuconfig@2022-09-17 - ncurses@6.5 - perl@5.38.2 - raja@2024.02.2 - zlib-ng@2.1.6
==> 6 installed packages
==> 12 concretized packages to be installed
```
$ spack -E find
...
==> 82 installed packages
```
56a1663cd9