`ConfigurationProvider.Current` shouldn't depend on `IConfigurationSectionHandler` from `System.Configuration.ConfigurationManager`

[bahusoid]

NHibernate-Caches/NHibernate.Caches.Common/ConfigurationProviderBase.cs

Lines 28 to 32 in 196296f

	public static ConfigurationProviderBase<TConfig, TConfigHandler> Current
	{
	get => _current ?? (_current = new StaticConfigurationManagerProvider());
	set => _current = value ?? new NullConfigurationProvider();
	}

It's quite strange that user custom implementation not using xml still needs dependency on this xml related class from nuget package:

public class CoreDistributedCacheCustomConfigProvider : ConfigurationProviderBase<CacheConfig,CoreDistributedCacheSectionHandler>