Stimuli section in database

[fietew]

TODOs:

• [x] add license for noise stimuli @hagenw (i would suggest CC0)
• [x] add description about creation of noise stimuli @hagenw
• [x] delete the "binaural" stimuli
• [x] add description about instrument stimuli

[fietew]

@hagenw: What is the current status?

[hagenw]

I can work on Thursday on this.

[hagenw]

I added the information, please review it and merge it.

At the moment there is no license under the instruments section. Is this missing or available in another branch?

[fietew]

missing