Fix handling of unsigned and zerofill in parser and normalization

[dbussink]

In the parser when generating a query, unsigned and zerofill are always rendered lowercase in canonical MySQL output.

Additionally, zerofill is deprecated for integer values similar to the length. Zerofill does still have a side effect though which is that it also does mark the field as unsigned.

The normalization now removes the zerofill attribute, but sets unsigned to true if it was used to keep this side effect.

Also see https://dev.mysql.com/doc/refman/8.0/en/numeric-type-attributes.html for the reference documentation on how this works.

Related Issue(s)

• schemadiff: tracking issue #10203

Checklist

• "Backport me!" label has been added if this change should be backported
• Tests were added or are not required
• Documentation was added or is not required

[github-actions]

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