Armbian next CI/pre switch adjustements

- bump version to 23.05
- adjust OCI repositories, changed hash lenght to 12 and removed rootfs- prefix to shorten names (costmetic adjustement)
- build configs were moved to https://github.com/armbian/os
- remove CI that is not going to work anymore. This means also master is out of this CI
- small changed to Readme.txt. Just adding some note, removing obvious
- add propery - supported arhitectures for distribution. Needed for CI optimisation
- remove README.armbian-next.md (need to be somewhere else)
- shrink CODEOWNERS due to messages overload

Signed-off-by: Igor <igor@armbian.com>

lib/functions/artifacts/artifact-uboot.sh

@@ -96,7 +96,7 @@ function artifact_uboot_cli_adapter_config_prep() {
 }
 
 function artifact_uboot_get_default_oci_target() {
-	artifact_oci_target_base="ghcr.io/rpardini/armbian-release/"
+	artifact_oci_target_base="ghcr.io/armbian/cache-uboot/"
 }
 
 function artifact_uboot_is_available_in_local_cache() {