Introduce virtual provider uuid (#18322)

libuuid is currently contained in util-linux, libuuid and uuid. This
change introduces a new virtual provider `uuid` and renames the existing
`uuid` package to `ossp-uuid`.

util-linux's libuuid is provided in the form of a separate package
util-linux-uuid to make sure that packages depending on uuid and
util-linux can use a separate uuid implementation, which the concretizer
does not allow if libuuid is contained in util-linux.

etc/spack/defaults/packages.yaml

@@ -49,6 +49,7 @@ packages:
       unwind: [libunwind]
       yacc: [bison, byacc]
       flame: [libflame, amdlibflame]
+      uuid: [util-linux-uuid, libuuid]
     permissions:
       read: world
       write: user