investigate caching strategy for chart api - see IMemoryCache #21
Description
Calls to the Chart API are expensive and repeat for the same symbol in a given session. We don't really need to update the chart every time, so caching the response for 5-10mins could reduce the cost.
https://learn.microsoft.com/en-us/aspnet/core/performance/caching/memory?view=aspnetcore-6.0