Limit visibility into layer2 connections

[jonstout]

Found a number of permissions related issues relating to l2 connections. There’s no workgroup_id passed to the following apis, and as they’re read operations on connections, they require checking if the user is in a workgroup that owns one of the interfaces or in the workgroup which owns the connection. We don't have a method to check this atm, so a resolution would involve two things.

• Method to check if user may view the connection
• Application of preceding method to listed apis

---
data.cgi:
  get circuit details: bad (requires adding workgroup_id param, or new conn perm check)
  generate clr: bad (requires adding workgroup_id param, or new conn perm check)
  get circuit details by external identifier: bad (requires adding workgroup_id param, or new conn perm check)
  get circuits by interface id: bad (read-only system users. not used by frontend)
  get circuit history: bad (read-only users) (requires adding workgroup_id param, or new conn perm check)
  get circuit sheduled evnets: bad (read-only users) (requires adding workgroup_id param, or new conn perm check)

measurement.cgi:
  get circuit data: bad (read-only users) (requires adding workgroup_id param, or new conn perm check)