Add API key field to user profile

[bajiat]

Implement API key field to user profile.

User story: As Minh (API consumer), I want to retrieve my API key.

Definition of done:

• Add API key field to user schema
• Add key preview field to user schema
• Add API key / preview field to profile page

[brylie]

We have at least two options for how to store the API Key data, in relation to the Meteor user.

• We can store the API Umbrella User data within the Meteor user object (e.g. user.profile.apiUmbrellaUser..)
• We can store the API Umbrella User data in a separate collection and have a 'foreign key' relationship in the Meteor user object (e.g. user.apiUmbrellaUser = key)

In the second case, we would write a collection helper to retrieve the correct API Umbrella User object from the ApiUmbrellaUsers collection, allowing traversal such as user.apiUmbrellaUser.apiKey.