Filter does not work for new vulnerability functions using newer version of GEM taxonomy

[pslh]

How to reproduce:
Open the "Vulnerability" tab in the Physical Vulnerability web app.
Note that there are many functions in the list including "CR+CIP/LPB", "CR/LRINF+DNO" etc.
Select Material "Concrete, reinforced" and press the "filter" button - an empty list is shown.

Cause
The newly added "Silva and Martins" functions have a name field corresponding to a new taxonomy string, but the "taxonomy gem" field is empty. At least some of the new models make use features from version 3 of the GEM taxonomy such as "DUM" and so are not compatible with the vulnerability DB software.

Related
This issue is related to gem/oq-platform-taxtweb#28; in both cases our software needs to be updated to handle the new version of the taxonomy.

[pslh]

Note also that for the same functions it is also impossible to export in NRML format (a server error is displayed) while it is possible to export older functions. I suspect our NRML export code is not ready to handle an empty GEM taxonomy string.

[hascar]

The newly functions that have a name field corresponding to a new taxonomy string actually are visualized with filter "Material -> Unknow Material" also if it's wrong.