Remove hard coded values in ddi_2_5-cessda_eqb.xslt

[borsna]

Hard coded values should be avoided.
Some example of hard coded values in the XSLT:

holdings:

ddi-xslt/transformations/cessda-eqb/from-ddi-2.5/ddi_2_5-cessda_eqb.xslt

Line 85 in 767774a

<holdings URI="http://www.adp.fdv.uni-lj.si/opisi/">Arhiv družboslovnih podatkov</holdings>

qstn@xml:lang:
https://github.com/MetadataTransform/ddi-xslt/blob/master/transformations/cessda-eqb/from-ddi-2.5/ddi_2_5-cessda_eqb.xslt#L170

labl@xml:lang:
https://github.com/MetadataTransform/ddi-xslt/blob/master/transformations/cessda-eqb/from-ddi-2.5/ddi_2_5-cessda_eqb.xslt#L209

var@xml:lang:
https://github.com/MetadataTransform/ddi-xslt/blob/master/transformations/cessda-eqb/from-ddi-2.5/ddi_2_5-cessda_eqb.xslt#L136

Values should come for source XML document or via xsl:param

[borsna]

@zibertg could you take a look at these cases?
The XSLT works fine but i think some hard coded values should be fixed so the XSLT works in a more general way for any DDI 2.5 XML-file.

Best regards,
Olof

[zibertg]

Agreed, for reuse of the XSLT hardcoded fields should be removed. Uploaded the updated XSLT.