Experiment collections and links to publications

[denkv]

User story

When I view an experiment in UI or as data in the database, I want to see if it's a part of some experiment group, as well as if an experiment or a group was included in some paper or other publication (with a link to the paper).

Solution

• add experiment collections/groups/lists
• define and use a way to link experiments and collections to publications

See also: #517