Remove Connect and ConnectAsync methods from IDistributedCache interface

[kichalla]

@lodejard brought up a good point of the need of having a Connect method on the interface. They seem to be implementation details for the particular distributed cache implementation (ex: RedisCache). SqlServerCache and LocalCache(distributed MemoryCache) do not require them.

https://github.com/aspnet/Caching/blob/dev/src/Microsoft.Extensions.Caching.Abstractions/IDistributedCache.cs#L10-L12

cc @Tratcher @muratg @Eilon @davidfowl

And regarding related issue #131, RedisCache can implement an IDisposable interface and in the dispose method can close the connections. Currently RedisCache is registered as singleton and the DI would call the Dispose method on the singleton instance(I verified this is happening)

[kichalla]

I have the following PR with the changes
#136

[Eilon]

@lodejard putting on your plate to review @kichalla 's PR at #136 and merge.

[basitanwer]

Guys why are we removing the Connect methods from IDistributedCache ?

I understand that SqlServerCache and LocalCache(distributed MemoryCache) do not require them but in reality they are not distributed caches.

Redis, NCache or any other distributed caches are very different and support different needs and they do not provided a connection pool therefore a Connect/Initialize method is a must.

[sebastienros]

@basitanwer If you look at the PR you will see how it works for Redis too. NCache won't be different. You can still do your own pool if necessary.