It should be possible to use empty salt provider without specifying LiveId compliance level

[aszczepanski]

Problem description

It's currently not possible to use empty salt provider without specifying LiveId compliance level.

Currently it's necessary to specify use configuration like

services.Configure<UserIdentiyMiddlewareOptions>(settings =>
{
  // Setting compliance level as LiveId to use empty salt provider
  settings.LoggingCompliance = UserIdentiyComplianceLevel.LiveId;
});

Proposed solution

• Make it possible to register required salt providers (by making them public) and make sure they can be registered and that the registration will be honoured.
• Or Rename/Add more compliance levels used in AddOmexMiddleware to be more generic (e.g. External, Managed or something similar)