library: Rename to libproc-2

library: Rename to libproc-2

What to call the new library?

Keep using libprocps wouldn't do, its a very different library from
the programs' point of view. It would also mean we could have some
clashes around the packages (two package names, same library name).

The ancient procps used libproc or libproc-a.b.c where a.b.c was the
package version. Kept the revision numbers down (it was always 0.0.0)
but the name of the library changed.

So if we use libproc-2 is there a clash with an ancient procps?
procps v 2.0.0 was around in 1999 so it was 22 years ago, also the
name of the library would have been libproc-2.0.0.so not libproc-2.so
so we're fine with that.

libproc-2 seems to fit, our second major re-work of the procps
library.

Signed-off-by: Craig Small <csmall@dropbear.xyz>