Implement IOptions accessor for MemoryDistributedCacheOptions

[JunTaoLuo]

Something we should have done in #336

[Tratcher]

You don't really need this. We only did it to MemoryCacheOptions so you could easily new up a MemoryCache (e.g. new MemoryCache(new MemoryCacheOptions())), because MemoryCache was something people were likely to create without DI. The same is not true for MemoryDistributedCache, it's only a DI fallback for a real IDistributedCache.

[JunTaoLuo]

I noticed this in Session when I was fixing the build, but that was only a test. If we are sure there's no use case for newing up an instance of MemoryDistributedCache then this isn't a big deal.

[JunTaoLuo]

Closing, if we need it, then we'll add it.