Frontend logging fixes

[achen2401]

Address https://www.pivotaltracker.com/story/show/188705822

• Add user info to each event logging
• Add analytics tag to tab/open/view events
• Prevent cosri-frontend tag from being added multiple times

Example JSONs posted

{
  "patient": "Barney Abbott",
  "message": "MME calculated: Name: Fentanyl Transdermal System, 0.05 mg/hr...",
  "level": "info",
  "tags": ["mme-calc", "cosri-frontend"],
  "patientName": "Barney Abbott",
  "subject": "Patient/5ee05359-57bf-4cee-8e89-91382c07e162",
  "user": { "username": "amysbubble" }
}

{
  "patient": "Barney Abbott",
  "message": "overview tab",
  "level": "info",
  "tags": ["tab", "analytics", "cosri-frontend"],
  "patientName": "Barney Abbott",
  "subject": "Patient/5ee05359-57bf-4cee-8e89-91382c07e162",
  "user": { "username": "amysbubble" }
}

[ivan-c]

Thank you! I tested on dev and found a minor inconsistency with the rest of our logs

[achen2401]

thank you @ivan-c for catching the inconsistency. I updated the description with updated user format in the JSON, e.g.

{
....
"user": { "username": "amysbubble" }
}

[ivan-c]

Found a minor issue. Tested on dev and looks good otherwise!