Proper model for PropertyValue values

[FoseFx]

Describe the chore

Currently, we cast it into an interface{}, which throws away vital information.

Is this a string because it's an option, or a text, or a multi-select option?

We could embrace TypedValue and give it proper serialization to esdb

[FoseFx]

I have to do this already in #841, so I'm self-assigning this one