Add support for multiple identifiers

[talavis]

Background

In order to "personalize" entries from the different facilities, add support for special names for entries created by teams.

• each team should be able to book one unique identifier
• any entry where the team is listed in editors can get the identifier
  • each entry can have identifiers from multiple teams, dois etc
• [odc]-team.identifier-<numbered id>
• identifiers may not be removed once added to an entry

Requirements

• Team identifier attribute for all teams
• Support for each order/dataset/collection to have multiple identifiers
  • _id is prefix + uuid
  • identifiers is a list of any other identifiers given to the entry
• keep counters for the team identifier somewhere (in team db entry?)
  • count all together, or one counter per data type?

**Depends on #40 **