Cache strategy for channels in ChannelService

Is your feature request related to a problem? Please describe. The ChannelService as-is holds an array of all channels in memory, which is updated whenever a channel is created/updated. This makes the vendure instance stateful and can lead to invalid/out-of-sync data if a project uses multiple vendure instances.

Describe the solution you’d like Querying from the database on every call would solve this, but since the data is used on every call (specifically getChannelFromToken) this would become a bottleneck. Querying the session data presented a similar bottleneck, so I think we need a similar solution. Similar to the SessionCacheStrategy config, I’d propose a ChannelCacheStrategy

[hendrik-advantitge]

I think there is nothing wrong with a lot of config options, as long as there are good default values. It gives options to the advanced users without getting in the way of new users.

[hendrik-advantitge]

You might have overlooked ShippingMethodService.activeShippingMethods