Provide a way to inspect available collections

[Kittyfisto]

It should be possible to provide a list of available collections, even when they cannot be interacted with because their types are (currently) unavailable.

Example code:

var db = Database.Open("database", ...);
foreach (var collection in Database.Collections)
{
    Console.WriteLine(collection.Name);
}

It should expose collections via the IReadOnlyCollection interface. A special implementation could be provided in case they key and/or value type are unknown / incompatible.

The following properties are of interest:

• name
• key type name
• key type (if available)
• value type name
• value type (if available)
• reason for not being available (e.g. KeyTypeUnavailable, ValueTypeIncompatible, etc...)