Add upload data icons to sidebar

[han-f]

When looking at the table with schemas (e.g. http://toep.iks.cs.ovgu.de/dataedit/schemas) or a table (e.g. http://toep.iks.cs.ovgu.de/dataedit/view/model_draft/szenarien_db_mmr) there will be the possibility to upload data with the wizard.

It would be great to also add a link to the API, so both ways to upload data are visible in the same place.

See also #662

1.) Icon Wizard (explanatory text: without prior knowledge, recommended for a single table)
2.) Icon API (explanatory text: programming skills required, recommended for multiple tables)