Add request headers into CloudWatch Logs

[paynejd]

CloudWatch is already enabled for OCL API and FHIR, but is capturing minimal data. We want to also capture request headers in preparation for using CloudWatch Insights

For staging, also change load balancer timeout to 2min and put a notification in place at 1min so that we can still track slow-running requests

[jamlung-ri]

@rkorytkowski Can you take a look at this and then address the Response Header follow-up ticket (#942)?

[snyaggarwal]

Added request user in Response headers as X-OCL-REQUEST-USER

[snyaggarwal]

Created #1116 to add response time in logs. There is no default Django way to do this, will have to write a custom middleware for this.
The rest of the tasks are done in this.
@rkorytkowski Please advise if we can close this out.