STYLE: use longer license name in SPDX identifier

- include mention of this repository location in the welcome message
  to make it easier for people to find and fork.

FIX: remove Leap workarounds for science repo

- importing of gpg keys now properly addressed in the dl.openfoam.com
  script, so can eliminate the workarounds here.

- the run scripts are largely identical to docker/podman solutions
  except no libnss wrapping needed, and sudo modification is disallowed

CONFIG: adjust for updated location of libnss_wrapper (ubuntu 22.04)