Added a config option to specify database error codes to ignore during updates #19578

Description:

Added a new config.ini.php option ignore_error_codes to specify database error codes that should always be ignored during database updates.

Fixes #19572

Review

• [ ] Functional review done
• [ ] Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• [ ] Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• [ ] Security review done
• [ ] Wording review done
• [ ] Code review done
• [ ] Tests were added if useful/possible
• [ ] Reviewed for breaking changes
• [ ] Developer changelog updated if needed
• [ ] Documentation added if needed
• [ ] Existing documentation updated if needed

Draft FAQ at https://matomo.org/?post_type=faq&p=56823&preview=true

@justinvelluppillai would you mind reviewing the FAQ regarding wording & grammar.

Looks great. Managed to find/fix a couple words, it's good to go grammatically now.

I've merged this and published the FAQ.