f6732865b9
This commit adds the information on how to install ScyllaDB without root privileges (with "unified installer", but we've decided to drop that name - see the page title). The content taken from the website https://www.scylladb.com/download/?platform=tar&version=scylla-5.2#open-source is divided into two sections: "Download and Install" and "Configure and Run ScyllaDB". In addition, the "Next Steps" section is also copied from the website, and adjusted to be in sync with other installation pages in the docs. Refs https://github.com/scylladb/scylla-docs/issues/4091 Closes #14781
