Add a way to configure a timeout for an API call

[arthuraraujo-msft]

          I'm confused after reading the implementation in CurlConnection.cpp. `maxRequestDuration` does appear to somewhat control the overall duration of the `GetLatestDowloadInfo` calls but not exactly. Why not change maxRequestDuration to mean the overall operation timeout and set a timeout for each "curl perform" equal to `min(<per-request-duration>, maxRequestDuration)? After a request fails, check your stopwatch against maxRequestDuration to decide whether to retry or not.

Originally posted by @shishirb-MSFT in #90 (comment)

[shishirb-MSFT]

Something like this:

struct RequestParams
{
    ...

    // Max time that this request is allowed to take. SFS client is free to perform
    // retries, control per-HTTP request timeout, etc., on its own while adhering 
    // to this overall timeout.
    std::chrono::milliseconds timeout = 30s;
};

[shishirb-MSFT]

The bool retryOnError that is being added in #90 can be retained even after adding this timeout.