Return well formatted authentication errors to the client
Log the reason for an error serveside but return a masked/generic reason to the client
Assert go errors by behavior rather than type.
If AccessedAt is left in the zero value, MySQL will complain with the following
error: Error 1292: Incorrect datetime value: '0000-00-00' for column 'accessed_at' at row 1. Now we initialize AccessedAt when creating a new
session.
This PR refactors most of the codebase to use the new config patterns implemented in #149. Now the core service keeps a copy of the KolideConfig struct, and service methods can reference the configuration in that struct when they need it. The most significant refactoring is in the sessions code, separating the business logic from the storage layer.
