Giacomo Cavallo Home assignment

[giacomocavallocg]

Description

This PR is the home assignment of Giacomo Cavallo and introduces an implementation of the ExchangeRateProvider for the Czech National Bank (CNB). The new provider fetches exchange rates from CNB’s API and includes a caching system to store the retrieved data.

Changes

• Implemented the ExchangeRateProvider class for retrieving exchange rates from CNB.
• Added an HTTP client to fetch exchange rates from the CNB API.
• Created a Cache interface and an in-memory cache implementation to optimize data retrieval.

Testing

• Verified successful retrieval of exchange rate data from CNB in a local environment.
• Tested handling of edge cases, such as null values or non-existent currencies.

Notes

This implementation retrieves only the most recent daily exchange rates as provided by CNB. The caching system uses an in-memory implementation, suitable for console applications. However, the Cache interface is designed to support easy integration with other caching systems, such as ASP.NET Core MemoryCache or Redis.