Crypto engine design enhancements and new library entry point

src/root.zig

@@ -1,2 +1,13 @@
-pub const packet = @import("packet.zig");
-// pub const crypto = @import("crypto.zig");
+const crypto = @import("crypto.zig");
+
+// This function is used to initialize the library
+// You can pass your own cryptographic functions to take advantage of your
+//    platform or use the library's software implementations for compatibility
+// Use its return value to access the library modules
+pub fn RnsZero(comptime cryptoProvider: crypto.PartialEngine) type {
+    const cryptoEngine = crypto.resolveEngine(cryptoProvider);
+    _ = cryptoEngine;
+    return struct {
+        pub const packet = @import("packet.zig");
+    };
+}