This commit improves forward compatibility of Spack with newer build cache metadata formats.

Before this commit, invalid or unrecognized metadata would be fatal errors, now they just cause
a mirror to be skipped.

Co-authored-by: Harmen Stoppels <[email protected]>

This changes variant display to use a much more legible format, and to use screen space
much better (particularly on narrow terminals). It also adds color the variant display
to match other parts of `spack info`.

Descriptions and variant value lists that were frequently squished into a tiny column
before now have closer to the full terminal width.

This change also preserves any whitespace formatting present in `package.py`, so package
maintainers can make easer-to-read descriptions of variant values if they want. For
example, `gasnet` has had a nice description of the `conduits` variant for a while, but
it was wrapped and made illegible by `spack info`. That is now fixed and the original
newlines are kept.

Conditional variants are grouped by their when clauses by default, but if you do not
like the grouping, you can display all the variants in order with `--variants-by-name`.
I'm not sure when people will prefer this, but it makes it easier to tell that a
particular variant is/isn't there. I do think grouping by `when` is the better default.

And improve the error message (load vs unload).

Of course you could have some uninstalled dependency too, but as long as
it doesn't implement `setup_run_environment` etc, I don't think it hurts
to attempt to load the root anyways, given that failure to do so is a
warning, not a fatal error.

The ^mkl pattern was used to refer to three packages
even though none of software using it was depending
on "mkl".

This pattern, which follows Hyrum's law, is now being
removed in favor of a more explicit one.

In this PR gromacs, abinit, lammps, and quantum-espresso
are modified.

Intel packages are also modified to provide "lapack"
and "blas" together.

Co-authored-by: Harmen Stoppels <[email protected]>

Co-authored-by: Harmen Stoppels <[email protected]>