add specific error messages, error codes, to serialize validation

[jonchurch]

draft take on #163 using a custom error class, and adding in the valid type of arg when its easy to do so.

[jonchurch]

No bencmarks for serialize yet, so not posting bench

[jonchurch]

@MaoShizhong don't mean to step on your contribution #163 here, started writing this before I saw your PR.

@wesleytodd I can see how error messages could be considered breaking changes for a package as widely used as cookie, aIthough I don't like it or what people would be depending on. The original change I was doing was just adding in the enriched error messages.

It does switch from TypeError to extending Error class, which is breaking since we were throwing TypeErrors before. instanceof CookieError !== 'TypeError'. I can swap it to TypeError extension, which would be nonbreaking for instanceof. But idk that feels weird? Should be named CookieSerializeValidationError or w/e at that point, instead of a generic error.

The breaking parts can be backed out, and @MaoShizhong could land the error codes independently in a minor.