Compare to Debian packaging of MariaDB 1:10.6.11-2 release at commit
https://salsa.debian.org/mariadb-team/mariadb-server/-/commit/2934e8a795cbd1eba79e33b8d6c82ed2b0897128
and sync upstream everything that is relevant for upstream and safe
to import on a stable 10.6 release.

* Use OpenSSL 1.1 from Debian Snapshots
  https://salsa.debian.org/mariadb-team/mariadb-server/-/commit/0040c272bf8a9a253fcd393b235b18cd5cdc9289
  Related: https://jira.mariadb.org/browse/MDEV-30322

* Prefer using bullseye-backports in mosts tests over buster-bpo
  https://salsa.debian.org/mariadb-team/mariadb-server/-/commit/daa827ecded9dc1f096ecb05242116173298d602

* Add new upgrade test for MySQL Community Cluster 8.0
  https://salsa.debian.org/mariadb-team/mariadb-server/-/commit/3c71bec9b7626d25a55e23b2e570b4e125d5d5df

* Enable automatic datadir move also on upgrades from MySQL.com packages
  https://salsa.debian.org/mariadb-team/mariadb-server/-/commit/4cbbcb7e56d9604a67230d11a68543d5a83960e3

* Update Breaks/Replaces
  https://salsa.debian.org/mariadb-team/mariadb-server/-/commit/2cab13d05959fe8f6ea56b866df51f3bfe17dd3f

* Normalize apt-get and curl commands
  https://salsa.debian.org/mariadb-team/mariadb-server/-/commit/8754ea2578bd214d75a2a9e6a0f7b4b74c062b41

* Standardize on using capitalized 'ON' in CMake build options
  https://salsa.debian.org/mariadb-team/mariadb-server/-/commit/938757a85aee44c727f3f6996677ef1126c2f5aa

* Apply wrap-and-sort -av and other minor tweaks and inline documentation

NOTE TO MERGERS: This commit is made on 10.6 branch and can be merged to
all later branches (10.7, 10.8, ..., 11.0).