Export of tags for harmonization

[AndyDaniel1]

We need an .csv export of all tags (duplicates excluded?) from the database when #2613 is completed so we can perform a harmonization of the tags.

The .csv file should contain the DAPID of all data packages that currently hold the specific tag (to be able to later merge the harmonized labels to the data packages). Maybe it would make sense to include columns for current and new tags. New tags should only be introduced if the old tag no longer fits.

Since the tags are available in German and English, we need to find a way to maintain the bindings of the two language versions. As the bindings are not explicitly modelled in the system, the en/de tags are technically independent of each other, but conceptually they should match. However as we have no technically binding we have to produce two independent tables for de/en

tag_current_de	tag_new_de	DAPID1	DAPID2	DAPID3	DAPIDn
Hochschulforschung	--	gra2005	ssy11	nac2018	....
Hochschulfochung	Hochschulforschung	gra2005	ssy11	nac2018	....

tag_current_en	tag_new_en	DAPID1	DAPID2	DAPID3	DAPIDn
Higher Education Research	--	gra2005	ssy11	nac2018	....
miation	migration	gra2005	ssy11	nac2018	....

[AndyDaniel1]

While we are in the process of harmonising the free tags, we should also consider to align the tags with the ELLST vocabulary (if possible).