Allow partial date values in dateOfBirth

[RuneBruijn98]

In the current Elmo scheme, it is not allowed for a person to have a partial date of birth. For example, a person can have a date of birth of "1998" (this is valid) but this value is not allowed in the .

We would like to change the dateOfBirth element so that it also allows a partial date value. For example:

[janinamincer-daszkiewicz]

Not a good idea. EWP needs the whole bday.

[RuneBruijn98]

Then we would like to change the simpleType to the following:

where a date like 1998-00-00 is also possible. If not, we would be excluding people from Emrex whilst having a valid date of birth according to European standards (ISO 8601).