Add SwiftUI demo project (#118)

* Commit after creating the project

* Add sherpa-onnx related files

* copy and modify files from sherpa-ncnn

* add app icon

ios-swiftui/SherpaOnnx/SherpaOnnx/Model.swift

@@ -0,0 +1,35 @@
+import Foundation
+
+func getResource(_ forResource: String, _ ofType: String) -> String {
+  let path = Bundle.main.path(forResource: forResource, ofType: ofType)
+  precondition(
+    path != nil,
+    "\(forResource).\(ofType) does not exist!\n" + "Remember to change \n"
+      + "  Build Phases -> Copy Bundle Resources\n" + "to add it!"
+  )
+  return path!
+}
+/// Please refer to
+/// https://k2-fsa.github.io/sherpa/onnx/pretrained_models/index.html
+/// to download pre-trained models
+
+/// sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20 (Bilingual, Chinese + English)
+/// https://k2-fsa.github.io/sherpa/onnx/pretrained_models/zipformer-transducer-models.html
+func getBilingualStreamZhEnZipformer20230220() -> SherpaOnnxOnlineTransducerModelConfig {
+  let encoder = getResource("encoder-epoch-99-avg-1", "onnx")
+  let decoder = getResource("decoder-epoch-99-avg-1", "onnx")
+  let joiner = getResource("joiner-epoch-99-avg-1", "onnx")
+  let tokens = getResource("tokens", "txt")
+
+  return sherpaOnnxOnlineTransducerModelConfig(
+    encoder: encoder,
+    decoder: decoder,
+    joiner: joiner,
+    tokens: tokens,
+    numThreads: 2
+  )
+}
+
+/// Please refer to
+/// https://k2-fsa.github.io/sherpa/onnx/pretrained_models/index.html
+/// to add more models if you need