This commit adds the upgrade guides relevant in version 2025.1: - From 6.2 to 2025.1 - From 2024.x to 2025.1 It also removes the upgrade guides that are not relevant in 2025.1 source available: - Open Source upgrade guides - From Open Source to Enterprise upgrade guides - Links to the Enterprise upgrade guides Also, as part of this PR, the remaining relevant content has been moved to the new About Upgrade page. WHAT NEEDS TO BE REVIEWED - Review the instructions in the 6.2-to-2025.1 guide - Review the instructions in the 2024.x-to-2025.1 guide - Verify that there are no references to Open Source and Enterprise. The scope of this PR does not have to include metrics - the info can be added in a follow-up PR. Fixes https://github.com/scylladb/scylladb/issues/22208 Fixes https://github.com/scylladb/scylladb/issues/22209 Fixes https://github.com/scylladb/scylladb/issues/23072 Fixes https://github.com/scylladb/scylladb/issues/22346 Closes scylladb/scylladb#22352