Track information for every log in event

[bobeagan]

We would like to keep a record of every log in event that occurs so that in the future we might act on things like suspicious activity or for providing audit reports for other business needs.

We will want to capture the following information for every log in event:

• timestamp
• IP address
• user agent string
• other device details

[spruce-bruce]

In order to get IP address we might need to work to understand the ways that oidc might be deployed.

Currently we do one of two things: ALB -> OIDC ALB -> nginx -> OIDC ELB -> ??? -> OIDC (not sure about this)

in the future we'll want to think about what it looks like in a kubernetes cluster possibly as well.

For this issue it'll just mean setting a reasonable requirement that can be met by all of those hosting setups, it's probably just going to be "make sure that the x-whatever-its-called-redirect" header thing is set.