Reverts passepartoutvpn/passepartout-apple#318
`Codable` compliance at the domain layer (`Profile` etc.) makes this
change in serialization destructive.
It's crucial that the data layer has full control over how entities are
(de)serialized.
Do not leave this choice up to the domain layer by defining an enum as a
raw value type, because any change in the enum raw value would literally
be a disaster, i.e. _any_ serialized data would break instantly.
* Make specific message levels a default extension
* Define Loggable protocol
* Keep track of message originator metadata
* Fix tracing of Core Data logs
* Log query on entity not found
