Add ReCClientOptions for configurable logging behavior

Introduce the `ReCClientOptions` class in the new `ReC.Client`
namespace. This class includes the `LogSuccessfulRequests`
property, which allows users to enable or disable logging for
successful API requests via the injected `ILogger`. Failed
requests are unaffected and will always throw `ReCApiException`.
The property defaults to `true`. XML documentation is included
to describe the class and its behavior.

src/ReC.Client/ReCClientOptions.cs

@@ -0,0 +1,16 @@
+namespace ReC.Client
+{
+    /// <summary>
+    /// Options that control the behavior of the <see cref="ReCClient"/>.
+    /// </summary>
+    public class ReCClientOptions
+    {
+        /// <summary>
+        /// Gets or sets a value indicating whether successful API requests should be
+        /// logged through the injected <see cref="Microsoft.Extensions.Logging.ILogger"/>.
+        /// Failed requests always throw <see cref="ReCApiException"/> regardless of this setting.
+        /// Defaults to <see langword="true"/>.
+        /// </summary>
+        public bool LogSuccessfulRequests { get; set; } = true;
+    }
+}