docs: Add Release 22 runtime example and crane to README (!3)
* Add short summary blurb at top of README.
* Add Release 22 example of a possible Python virtual environment.
* Add crane as an alternative to tracking the TWikis.Please be advised that registry.cern.ch and registry-tn.cern.ch registries (Registry Service) will be unavailable next Tuesday, Feb 11th starting at 08:00h (Geneva time) for a short period of time. This may cause temporary disruptions to your workflows. Further info: OTG0154380
* Add short summary blurb at top of README.
* Add Release 22 example of a possible Python virtual environment.
* Add crane as an alternative to tracking the TWikis.