ADD COMET_FORMAL_MODE option in config.sh

[fisuda]

Proposed changes

This PR adds COMET_FORMAL_MODE option in config.sh.

Types of changes

What types of changes does your code introduce to the project: Put an x in the boxes that apply

• [ ] Bugfix (non-breaking change which fixes an issue)
• [X] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Update docker image version of FIWARE GE.
• [X] Update only documentation, not any source code.

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• [X] I have read the CONTRIBUTING doc
• [ ] I have signed the CLA
• [X] I have updated the change log (CHANGELOG.md)
• [X] I send this pull request to the v0.37.0-next branch.
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have added necessary documentation (if appropriate)
• [ ] Any dependent changes have been merged and published in downstream modules

Further comments

N/A

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 86.75%. Comparing base (16c2d83) to head (ffd4d4f).

Files	Patch %	Lines
CHANGELOG.md	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## v0.37.0-next #376 +/- ## ================================================= - Coverage 100.00% 86.75% -13.25% ================================================= Files 1 2 +1 Lines 1781 2054 +273 ================================================= + Hits 1781 1782 +1 - Misses 0 272 +272 ```

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