Token services

[andreareginato]

Add token services to generate tokens via API. This is really important if we want to build the invitation system, which is based on the generation of tokens.

[andreareginato]

It must allow you to set

• accessible devices
• accessible locations
• expiring time (with expires_at)
• available actions (use scopes)
• source ip (IP address that access should be restricted to) ??

See cosm to see an implementation of key definition.