Adding Integration Tests for mysql_db module

Adding the following Test Coverage for RedHat and Debian OS:

 - Use mysql_db module to create, delete databases using different encoding.
 - Backup/Restore databases using different file format: sql, gz and bz2.
 - Create and delete databases using different user privilege.
 - Assert database creation, deleting and content using system commands.

test/integration/roles/setup_mysql_db/defaults/main.yml

@@ -0,0 +1,6 @@
+mysql_service: mysqld
+
+mysql_packages: 
+    - mysql-server
+    - MySQL-python
+    - bzip2