Add "contains_none" rule to cell validation

[SmetDenis]

This update introduces a new rule named "contains_none" to the cell validation process. This rule takes an array of strings and validates that none of these strings appear in the cell value. Changes have been incorporated in the relevant schema example files and the associated PHP and Test files for the new validation rule have been created.

[coveralls]

Pull Request Test Coverage Report for Build 8426723736

Details

• 15 of 15 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.03%) to 96.381%

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Totals
Change from base Build 8426544754:	0.03%
Covered Lines:	1731
Relevant Lines:	1796

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💛 - Coveralls