4.0 | Remove previously deprecated code

[jrfnl]

Removing the deprecated JS sniffs is tracked separately in #442.

List of deprecated code which should be removed in the next major:

• [ ] WordPressVIPMinimum\Sniffs\Classes\DeclarationCompatibilitySniff::$checkClasses - deprecated since VIPCS 3.1.0, see #858, related to #234.
• [ ] WordPressVIPMinimum\Sniffs\Classes\DeclarationCompatibilitySniff::$checkClassesGroups - deprecated since VIPCS 3.1.0, see #858, related to #234.
• [ ] The complete WordPressVIPMinimum\Sniffs\Functions\DynamicCalls sniff - deprecated since VIPCS 3.1.0, see #517 and #865
• [ ] WordPressVIPMinimum\Sniffs\Performance\TaxonomyMetaInOptionsSniff::$option_functions - deprecated since VIPCS 3.1.0, see #872, related to #234.
• [ ] WordPressVIPMinimum\Sniffs\Security\ProperEscapingFunctionSniff::$url_attrs - deprecated since VIPCS 2.3.1
• [ ] WordPressVIPMinimum\Sniffs\Security\ProperEscapingFunctionSniff::$attr_endings - deprecated since VIPCS 2.3.1
• [ ] WordPressVIPMinimum\Sniffs\Security\ProperEscapingFunctionSniff::attr_expects_url)_ - deprecated since VIPCS 2.3.1
• [ ] WordPressVIPMinimum\Sniffs\Security\ProperEscapingFunctionSniff::is_html_attr() - deprecated since VIPCS 2.3.1

[jrfnl]

Work in Progress branches which should help to address this when the time comes:

• WAIT-VIPCS4.0/feature/849-remove-deprecated-properties-methods
• WAIT-VIPCS4.0/feature/849-functions-dynamiccalls-remove-deprecated-sniff