Use a separate configuration file with OTRS mysql recommended settings

instead of replacing the values on the default musql config file. Fixes
issue #76.

mariadb/Dockerfile

@@ -7,11 +7,12 @@ ENV MYSQL_ROOT_PASSWORD changeme
 USER root
 
 #Change db configuration as required by official install docs and Enable utf8 support
-RUN sed -i.bk -r '/^\[mysqld\]$/a max_allowed_packet=64M' /etc/mysql/my.cnf && \
-    sed -i.bk -r '/^\[mysqld\]$/a query_cache_size=32M' /etc/mysql/my.cnf && \
-    sed -i.bk -r '/^\[mysqld\]$/a innodb_log_file_size=256M' /etc/mysql/my.cnf && \
-    sed -i.bk -r '/^\[mysqld\]$/a skip-character-set-client-handshake' /etc/mysql/my.cnf && \
-    sed -i.bk -r "/^\[mysqld\]$/a init_connect='SET collation_connection = utf8_unicode_ci'" /etc/mysql/my.cnf && \
-    sed -i.bk -r '/^\[mysqld\]$/a collation-server = utf8_general_ci' /etc/mysql/my.cnf && \
-    sed -i.bk -r "/^\[mysqld\]$/a init-connect=\'SET NAMES utf8\'" /etc/mysql/my.cnf && \
-    sed -i.bk -r '/^\[mysqld\]$/a character-set-server = utf8' /etc/mysql/my.cnf
+RUN echo "[mysqld]" >> /etc/mysql/conf.d/otrs.cnf &&\
+    echo "max_allowed_packet=64M" >> /etc/mysql/conf.d/otrs.cnf &&\
+    echo "query_cache_size=32M" >> /etc/mysql/conf.d/otrs.cnf &&\
+    echo "innodb_log_file_size=256M" >> /etc/mysql/conf.d/otrs.cnf &&\
+    echo "skip-character-set-client-handshake" >> /etc/mysql/conf.d/otrs.cnf &&\
+    echo "init-connect='SET NAMES utf8'" >> /etc/mysql/conf.d/otrs.cnf &&\
+    echo "init_connect='SET collation_connection = utf8_unicode_ci'" >> /etc/mysql/conf.d/otrs.cnf &&\
+    echo "collation-server = utf8_general_ci" >> /etc/mysql/conf.d/otrs.cnf &&\
+    echo "character-set-server = utf8" >> /etc/mysql/conf.d/otrs.cnf