Correct logging in ph5_validate like other ph5 tools

[damhuonglan]

What does this PR do?

ph5_validate build logging in a way that different with other ph5 tools' which makes others when they are called in unittest keep calling ph5_validate.log for their logging file if they don't have their own. It doesn't affect other tools' functions but make unittest checks failed. Currently the check in PR #383 are failed because of this problem.

This PR correct the logging in ph5_validate to be the same as others

Checklist

• [ ] This PR is not directly related to an existing issue (which has no PR yet).
• [ ] All tests pass.
• [ ] Any new or changed features have are documented.
• [ ] Changes have been added to CHANGELOG.txt .
• [ ] First time contributors have added your name to CONTRIBUTORS.txt .

[damhuonglan]

@MaevaP Thanks for reviewing the PR for me. However some of your reviews are seem to be on the lines that no longer exist. I add "This part of code is outdated" under those lines. I changed outfile to args.outfile according to your recommendation, added help for outfile and kept the line for setting formatter and level for logging.