[Swift] Object API support (#5826)

* Adds Object-api support to swift

* Fixed indentation issues

* Removed indentation within namespaces

swift/Sources/FlatBuffers/FlatBufferObject.swift

@@ -6,6 +6,14 @@ public protocol FlatBufferObject {
     init(_ bb: ByteBuffer, o: Int32)
 }
 
+public protocol NativeTable {}
+
+public protocol ObjectAPI {
+    associatedtype T
+    static func pack(_ builder: inout FlatBufferBuilder, obj: inout T) -> Offset<UOffset>
+    mutating func unpack() -> T
+}
+
 /// Readable is structures all the Flatbuffers structs
 ///
 /// Readable is a procotol that each Flatbuffer struct should confirm to since