Support configuration options for cache entries (MemoryCache)

[pergerch]

Introduce nullable properties in the [Cache] attribute to set MemoryCacheEntryOptions for cache entries.

These 3 properties should be implemented and if set, passed to the MemoryCache.Set call by using the MemoryCacheEntryOptions parameter:

• int AbsoluteExpirationRelativeToNow (in seconds)
• int SlidingExpiration (in seconds)
• CacheItemPriority Priority

Code sample:

[Cache(SlidingExpiration = 10, Priority = CacheItemPriority.Low)]
public class BasicSample
{
 // ...
}