Main: Added inital support for Debian 11

Added Debian 11 as supported os
Added deb11 to all places were deb10 was in a if statement

Temporarily replaced MySQL with MariaDB,
since the MySQL repo is not yet avalible

SubModules/redis/preconf.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-if [ "$shortdist" = "ubu1804" ] || [ "$shortdist" = "ubu2004" ] || [ "$shortdist" = "deb10" ] ; then
+if [ "$shortdist" = "ubu1804" ] || [ "$shortdist" = "ubu2004" ] || [ "$shortdist" = "deb10" ] || [ "$shortdist" = "deb11" ] ; then
 # Debian/Ubunbtu redis variables
     redisService=redis-server