Support authenticated connections

Created by: rjw57

Currently the lookup connection is created in ucamlookup.utils by simply calling createConnection. Extend this to allow configuration of the connection by Django settings. This will allow using a group's credentials to authenticate.

Suggested settings:

• UCAMLOOKUP_HOST. Optional. Default: "www.lookup.cam.ac.uk"
• UCAMLOOKUP_PORT. Optional. Default: 443
• UCAMLOOKUP_URL_BASE. Optional. Default: ""
• UCAMLOOKUP_CHECK_CERTS. Optional. Default: True
• UCAMLOOKUP_USERNAME. Optional. Default: None
• UCAMLOOKUP_PASSWORD. Optional. Default: None.

Apart from the username and password settings, these are passed directly to the IbisClientConnection constructor. If non-None, the username is set on the connection via the set_username method. If non-None, the password is set on the connection via the set_password method.

Created by: rjw57

I've just had verbal confirmation from AIS that global authenticated access to Lookup should go live by Match 7th 2019.

This has gone live now so this issue is unblocked.

changed milestone to %Sprint 66

assigned to @rjw57

added workflowIn Progress label

removed workflowIn Progress label

unassigned @rjw57

added workflowIn Progress label

assigned to @amc203

mentioned in merge request !6 (merged)

added workflowNeeds Deployment label and removed workflowIn Progress label

closed via merge request !6 (merged)

mentioned in commit f949ddb4

removed workflowNeeds Deployment label

mentioned in issue uis/devops/devhub/docs#70 (closed)