Build multiple index files with template

[marcerich]

It seems that only one index.md is currently transformed to html. Sometimes there are additional index files in sub directories. Would be nice if we would build these also with the template.

More general, maybe a similar function to <*>-deck.md, e.g., using <*>-idx.md would be nice. However, we also want to generate the unique index.html of course. So in contrast to the handling of decks one could throw the suffix -idxaway.

[monofon]

That is a good idea. But I think just calling that file index.md is sufficient because, by definition of index, there shoud be only one per directory.