Improve CI/CD compatibility

• Replace the 'copy' module with 'template' for dblab_engine_config_file variable
  • for the possibility of redefining values through variables.
• Fix the ability to exec a playbook with a tag
  • previously, all roles were performed even if one tag was specified in the --tags option

Additionally

• Update ansible.cfg to reduce the number of WARNING messages regarding empty inventory
  • we are generating a dynamic inventory using 'add_host' module so the file is missing