Adding a picture and potentially a short description field to Asset and Participant objects

[xamcost]

Hi there! I am opening this issue to suggest two things:

1. the addition to the Asset and Participant object of a picture field, which would be a url pointing to an image. The idea of this is to enable them to illustrate an Asset or Participant display in the marketplace with a logo. It is a low hanging fruit and would make the marketplace more appealing.
2. the addition of a short_description field in the Asset object, which would just be text. Its goal is to be a one sentence summary of what should be in the longer description field. This is to enable prospective consumer to have a quick overview of the asset in the offering.

I suggested adding these fields in Asset, but if you think it fits better elsewhere, such as in AssetProvision, let me know.