Add more metadata (e.g. topics) to dataset list

[alastair]

In our own internal lists of datasets we have additional metadata that we can search/filter by.
One useful item is the "topic" tag, which is a broad MIR task that we can filter datasets by. This allows us to see at a glance all datasets that are generally useful for autotagging/genre recognition/bpm recognition/key detection/etc

I think it'd be a good idea to allow a topic tag in entries in this list, so that in the future we can think about ways of presenting the data.

I'm open to other types of metadata annotations too. Perhaps it makes sense to formalise a set of fields that can be used for filtering:

• audio/features
• feature types (MFCC, ...)?
• annotation format

[stefan-balke]

Hey @alastair,

was today thinking the same and saw your issue.
Do you have some kind of documentation on your current tags?
Genre could also be interesting if appicable.