Provide functionality to search a taf/tap within library

[henryk86]

If you want to assign a new source in the new web frontend and have many files in your library, a search function would be very helpful. You could pass a search string to this API and, analogous to the current special parameter, whether content or library (necessary/useful?) and then receive all matching files including the path as a response.

So the cherry on the cake would be the support of the search via the entries in the tonies(.custom).json at this point.
So that the search for Asterix also returns all Taf files where the corresponding entries in the jsons have asterix in a tag...
but that would really be the icing on the cake!

Kind of the Search Model functionality only for taf/tap files.