Unify runtime tagging scheme of values

[davazp]

We have a few different mechanism we use to tag CL values at runtime.

We have storage-vectors, dt_ tags, and other tags to implement arrays and strings.

I think it would be a good idea to have a more unified approach. Possibly, extending storage-vector to have stoarge-map or storage-object and be able to have some tag that we can use in the implementation of the types.

[vlad-km]

Let's just say it's the traditional way. For all such objects, a special single tag is checked against a standard bit mask.