TT#35502 Replace Requires=mysql.service with Wants=mariadb.service for ngcp-mediator.service

Is service B "Requires" service A to be started before B
and B does NOT require B restart on A restart, B should use "Wants=A".
Also using real service name mariadb.service instead of alias one.

The same for redis-server.service.
Also migrate from alias mysql.service to mariadb.service.

Change-Id: I94276a8647053646abd545e4d5b768b284b8a652

debian/ngcp-mediator.service

@@ -1,10 +1,10 @@
 [Unit]
 Description=NGCP Mediator
-After=mysql.service
+After=mariadb.service
 After=redis-server.service
 After=remote-fs.target
-Requires=mysql.service
-Requires=redis-server.service
+Wants=mariadb.service
+Wants=redis-server.service
 
 [Service]
 Type=simple