Change typescript type of .tag() from string to any

[jsobell]

The tag field is associated with a rule, so there's not really any need specify it as a string, as it can also be used to associate metadata with a rule.
@dkent600 wants to pass a list of associated properties to his renderer for object level rules, and of course this can also apply to property linked rules if they have (v.obj) => obj.anotherProperty==true.
If we leave it as type any it can also be used for its original intention but with more advanced filtering.

This also (I think) covers #279 (comment) and #351

[dkent600]

@jsobell Can you please give an example of how a developer would use this to address 279 (comment) and #351?

Thanks

[jdanyow]

I don't think tag will solve the two issues but keeping this open for non-string tags.

[jdanyow]

Closing- there are some data-binding capabilities I want to add that would enable binding to the validity of a tagged rule. Keeping the tag arg a string will make this easier/more-consistent.