Add check about permissions folder for tmp/service_logs

[mrodm]

There has been some times, that the folder .elastic-package/tmp/service_logs is owned by a different user and tests could not write the required files in that folder.

That folder is used in tests through the placeholder SERVICE_LOGS_DIR.

It would be helpful to add a check to detect the permisisons and ownership of this folder. If that folder cannot be changed to the desired permissions, probably elastic-package should fail with an error about it.

[jsoriano]

#1852 looks like a good solution to this problem.