mariadb: convert init script to procd

- also adds mariadb user to run the server as
- tweaks the default configuration a bit

Signed-off-by: Sebastian Kemper <sebastian_ml@gmx.net>

utils/mariadb/conf/mysqld.default

@@ -0,0 +1,10 @@
+# The user and group that will run the MySQL server. The user mariadb is
+# automatically created by the mariadb-server package, hence that is the
+# default choice.
+
+#MY_USER=mariadb
+#MY_GROUP=mariadb
+
+# Additional arguments you want to pass to the MySQL server.
+
+#MY_ARGS=""