Download table view option

[sebastian-nehrdich]

We need a download option for the table-view with the following features:

• download with the current filter/sorting settings
• some common output format, for example excel
• possibly we need a different limit for the number of entries than in the current pagination - something between 1000 and 10000 should work
  • a button on the frontend is needed - maybe right hand side of the external link box (that leads to CBETA/SC/GRETIL/rKTs)?