feat: 切换后端至PaddleOCR-NCNN，切换工程为CMake

1.项目后端整体迁移至PaddleOCR-NCNN算法，已通过基本的兼容性测试
2.工程改为使用CMake组织，后续为了更好地兼容第三方库，不再提供QMake工程
3.重整权利声明文件，重整代码工程，确保最小化侵权风险

Log: 切换后端至PaddleOCR-NCNN，切换工程为CMake
Change-Id: I4d5d2c5d37505a4a24b389b1a4c5d12f17bfa38c

3rdparty/ncnn/tools/pnnx/tests/test_torch_cat.py

@@ -0,0 +1,59 @@
+# Tencent is pleased to support the open source community by making ncnn available.
+#
+# Copyright (C) 2021 THL A29 Limited, a Tencent company. All rights reserved.
+#
+# Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
+# in compliance with the License. You may obtain a copy of the License at
+#
+# https://opensource.org/licenses/BSD-3-Clause
+#
+# Unless required by applicable law or agreed to in writing, software distributed
+# under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+# CONDITIONS OF ANY KIND, either express or implied. See the License for the
+# specific language governing permissions and limitations under the License.
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+class Model(nn.Module):
+    def __init__(self):
+        super(Model, self).__init__()
+
+    def forward(self, x, y, z, w):
+        out0 = torch.cat((x, y), dim=1)
+        out1 = torch.cat((z, w), dim=3)
+        out2 = torch.cat((w, w), dim=2)
+        return out0, out1, out2
+
+def test():
+    net = Model()
+    net.eval()
+
+    torch.manual_seed(0)
+    x = torch.rand(1, 3, 16)
+    y = torch.rand(1, 2, 16)
+    z = torch.rand(1, 5, 9, 11)
+    w = torch.rand(1, 5, 9, 3)
+
+    a0, a1, a2 = net(x, y, z, w)
+
+    # export torchscript
+    mod = torch.jit.trace(net, (x, y, z, w))
+    mod.save("test_torch_cat.pt")
+
+    # torchscript to pnnx
+    import os
+    os.system("../src/pnnx test_torch_cat.pt inputshape=[1,3,16],[1,2,16],[1,5,9,11],[1,5,9,3]")
+
+    # pnnx inference
+    import test_torch_cat_pnnx
+    b0, b1, b2 = test_torch_cat_pnnx.test_inference()
+
+    return torch.equal(a0, b0) and torch.equal(a1, b1) and torch.equal(a2, b2)
+
+if __name__ == "__main__":
+    if test():
+        exit(0)
+    else:
+        exit(1)