4ebae7ae62
This commit adds the upgrade guide from version 2025.1 to 2025.2.
Also, it removes the upgrade guides existing for the previous version
that are irrelevant in 2025.2 (upgrade from OSS 6.2 and Enterprise 2024.x).
Note that the new guide does not include the "Enable Consistent Topology Updates" page,
as users upgrading to 2025.2 have consistent topology updates already enabled.
Fixes https://github.com/scylladb/scylladb/issues/24133
Fixes https://github.com/scylladb/scylladb/issues/24265
Closes scylladb/scylladb#24266
(cherry picked from commit 8b989d7fb1)
Closes scylladb/scylladb#24391