Improve how caching is done within the service

[millicentachieng]

We currently use various caching mechanisms within DevX API: MemoryCache, ConcurrentDictionary etc.

Points to explore:

• How frequent should we refresh cache?
• Can multiple threads concurrently write to the same cache? What's the impact in terms of data consisitency, cost?
• Can we have a ,different process, e.g. a webjob, be responsible for refreshing the caches
• Should we bring a library (like Lazy Cache) to handle the caching for us?
• ASP.NET background tasks?

Resources

• Background tasks with hosted services in ASP.NET Core
• How do I put data in a MemoryCache on startup?

cc @baywet