Processing level - revised

[lavanya3k]

Description of the PR - This is a pull request for code changes for ProcessingLevel/ProcessingLevelDescription.

ProcessingLevel/LevelDescription - We will provide a detailed description if the characters are less than 50 characters. The suggested recommendation is,
Processing Level Description:

If the processing level description field is missing, the following message should appear (BLUE/Info):
"Recommend providing a processing level description, using the EOSDIS processing level descriptions as guidance:
https://www.earthdata.nasa.gov/engage/open-data-services-and-software/data-information-policy/data-levels"

If a processing level description is provided but it has fewer than 50 characters, then the following message should appear (BLUE/Info):
"The description provided is under 50 characters. Recommend providing a more detailed processing level description, using the EOSDIS processing level descriptions as guidance:
https://www.earthdata.nasa.gov/engage/open-data-services-and-software/data-information-policy/data-levels"

Code changes: The code changes are included in the check_messages_override.json and rules_override.json. Further, we updated the outdated files in the test_downloader.py and schema_validator.py. There was an outdated imports DraftValidator, and this has to be updated before every commit. The final code is test by running pytest, and the run was successful before committing the code changes.

To Reproduce:
C1000000003-CDDIS --format umm-c - Processing level description.
C1000000018-CDDIS --format umm-c - Processing level description.
C2043197582-CDDIS --format umm-c - Processing level ID and description. (Processing level ID is addressed in #320)
C1602481912-CDDIS --format umm-c - Processing level description < 50 characters.

Expected output:

[FBayat021]

For the processing level ID, we need to refer to the URL provided by ESDIS:
https://gcmd.earthdata.nasa.gov/kms/concepts/concept_scheme/ProductLevelId?format=json

If an ID does not exist in the above URL, we cannot include it in our library check.
We are currently awaiting further information and clarification from ESDIS.

[lavanya3k]

Processing level ID is addressed separately at #320

[lavanya3k]

Tested in the dev branch for processing level description (two scenarios), and it works.

Expected outcome: