feat: add validator for numeric ports

[nodivbyzero]

Fixes Or Enhances

This PR adds a new validation for numeric ports.
Connected to: #1216

	type Host struct {
		Port uint32 `validate:"port"`
	}

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• Tests exist or have been written that cover this particular change.

@go-playground/validator-maintainers

[coveralls]

coverage: 74.298% (+0.007%) from 74.291%
when pulling 70d0cd0 on nodivbyzero:feat-numeric-port-validation
into a947377 on go-playground:master.