Adding the "severity" option to the logging module.

[awhaley-dell]

SUMMARY

Added the new severity option to the logging module.
Updated the unit tests, regression tests, and related module utils for the logging module in order to add functionality for the severity parameter.

GitHub Issues

N/A

ISSUE TYPE

• Feature Pull Request

COMPONENT NAME

sonic_logging : severity

OUTPUT

Logging module regression run pass results and log file:
logging-severity-option-regression-run.pdf
logging-severity-option-regression-run-text-output.log

Checklist:

• I have performed a self-review of my own code to ensure there are no formatting, linting, or security issues
• I have verified that new and existing unit tests pass locally with my changes
• I have not allowed coverage numbers to degenerate
• I have maintained at least 90% code coverage
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I have maintained backward compatibility or have provided any relevant "breaking_changes" descriptions in a "fragment" file in the "changelogs/fragments" directory of this repository.
• I have provided a summary for this PR in valid "fragment" file format in the "changelogs/fragments" directory of this repository branch. Reference : Ansible Change Log Document