Remove unnecessary `Name` property from completion providers

[DoctorKrolic]

It was only used to enrich context for logging. However, since logger already takes source type as context and every provider has a unique name, I consider it unnecessary. Even if we for whatever reason want to enrich logger with more type-related data, we better use something like GetType().Name. Since logs are used to investigate things, having a direct type name there would be better. But again, I don't think that even this thing is necessary since we provide type as context anyway.

@tintoy I would like your approval on this before merging

[tintoy]

That sounds pretty reasonable to me :)