Include the details about 10.4 to 10.5 and newer major versions upgrades for Galera clusters into the Knowledge Base

In https://mariadb.com/kb/en/upgrading-galera-cluster/ we see that major version upgrade instructions end up with 10.3 t 10.4 upgrade:

https://mariadb.com/kb/en/upgrading-from-mariadb-103-to-mariadb-104-with-galera-cluster/

WE need similar detailed step for 10.4 to 10.5, 10.5 to 10.6, 10.6 to 10.7 and 10.7. to 10.8 upgrades, maybe in a single document if there is no real difference (but I assume some details may still differ for upgrade from 10.5 to 10.6, for example). Then we need a page added for each major release before it is declared GA.