Add CESSDA SKG-IF API in Tools

[markusjt]

Adds a page about CESSDA SKG-IF API in SKG Tools. I had to add some notes and a warning on the page due to there being some issues currently that will hopefully be fixed soon but might actually not happen until January.

Edit: Changed to draft as there is a chance that these issues will be fixed tomorrow so I'll change this back to ready for review tomorrow (19 Dec) afternoon.

[MarekSuchanek]

@markusjt there are conflicts again... can you either give me access so I can rebase and directly merge or can you rebase and let me know? Seems there are conflicts in SKG.rst where style was changed (4 space indentation instead of 3).

[markusjt]

@markusjt there are conflicts again... can you either give me access so I can rebase and directly merge or can you rebase and let me know? Seems there are conflicts in SKG.rst where style was changed (4 space indentation instead of 3).

Does it work now? I fetched upstream and rebased but somehow made a slight mistake somewhere I think as then I had 3 space indentation for the tools in SKG.rst only so I fixed that in a separate commit.

[MarekSuchanek]

Thanks, I merged it to avoid any more of unnecessary rebasing... @TomMiksa and @andresTabiTuwien can then do adjustments as part of #22.