Add support for xsd("auto")

[laurianvm]

consider making the | xsd filter a bit smarter:
Add xsd("auto"), which applies the best fitting xsd type to the actual datatype

(copying from IMIS-1598)

[cedricdcc]

@laurianvm are you working on this actively?
Also can you explain the diff/example why this issue and issue #115 ?

[marc-portier]

@cedricdcc the description seems clear

1. Add support for xsd("auto") #116 --> | xsd("auto") will apply an xsd type that matches the python-type passed in (which assumes some smartness in the Source implementation that does proper type conversion, or assumes the template is doing that type conversion)
2. Add support for xsd("detect") #115 --> `| xsd("detect") will ignore the input type, assume str (or even force conversion) and then make a guess of the type before handing it over to the appropriate matching xsd-type

In other words:
| xsd(detect) == | do-str-to-type-detection-and-conversion +| xsd(auto)