Add text prompt support

src/Spectre.Console/IAnsiConsoleInput.cs

@@ -0,0 +1,17 @@
+using System;
+
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Represents the console's input mechanism.
+    /// </summary>
+    public interface IAnsiConsoleInput
+    {
+        /// <summary>
+        /// Reads a key from the console.
+        /// </summary>
+        /// <param name="intercept">Whether or not to intercept the key.</param>
+        /// <returns>The key that was read.</returns>
+        ConsoleKeyInfo ReadKey(bool intercept);
+    }
+}