Implement caching in the ClientProvider

[TwiN]

Implementing a cache with a configurable TTL as well as a configurable maximum size in ClientProvider could be very useful to help preventing unnecessary load on whatever service or infrastructure component ClientProvider's getClientByTokenFunc function is calling.

The implementation:

• Must be able to have a maximum cache size (e.g. 10000)
• Must be able to have a configurable TTL (e.g. 1 hour)
• Must be able to cache invalid tokens with a shorter entry TTL (e.g. 30 minutes)

Being the self-promoting person that I am, I think TwinProduction/gocache would fit this role perfectly.

[ynden]

Hi Chris, I would like to give it a shot.
Thanks