Values can be represented in a variety of units. However, to make queries against the data, we need to bring the compatible values - such as distance expressed in meters, kilometers or miles - to a common normalized value. Thus, we need a data item that expresses the normalized value of the claim.
In order to do that, we will have additional value attached to statement/qualifier/reference with normalized values - i.e. in addition to `psv:`, `pqv:` and `prv:` we also have `psn:`,`pqn:` and `prn:` respectively.
These values will be generated for now for values of type `datetime` and `quantity` only, as only these types need to be normalized.
The value will contain "normalized" value, as follows:
* For quantity, it will be the main unit value, converted according to conversion rules in configuration (TBD)
** Upper/lower bound values are converted too
* For datetime, it will be converted Gregorian ISO value, while the main value is converted to string value