External Authentication - LDAP/AD/SAML

[hhydes]

Is your feature request related to a problem? Please describe.
It is a little annoying when you have to manually create users and user details. Being able to use Central Authentication with groups that provide the required access (Either to specific features or Specific Client Access)

Describe the solution you'd like
It would be useful to be able to use external authentication with role based groups for accessing Tactical.

[dinger1986]

This is already requested in #508, please add there