support for multiple teams

[anoff]

allow multi-tenant use by introducing a teams element. general idea:

1. 1 token = 1 user
2. 1 token can be long to 0-1 teams
3. data is shared within a team by changing all read operations to check if specific uploads have been made by this team's tokens

main concerns:

1. current handling of planet data does not support multi tenants, either need to introduce submitted_by column (which would make location no longer unique in the table) or create one planets table per team