Ubuntu 22.04 is supported by both ScyllaDB Open Source 5.0 and Enterprise 2022.1.
Closes#11227
* github.com:scylladb/scylladb:
doc: add the redirects from Ubuntu version specific to version generic pages
doc: remove version-speific content for Ubuntu and add the generic page to the toctree
doc: rename the file to include Ubuntu
doc: remove the version number from the document and add the link to Supported Versions
doc: add a generic page for Ubuntu
doc: add the upgrade guide from 5.0 to 2022.1 on Ubuntu 2022.1
(cherry picked from commit d4c986e4fa)