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/opencv-4.5.4/modules/python/test/test_gaussian_mix.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python
+
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    xrange = range
+
+import numpy as np
+from numpy import random
+import cv2 as cv
+
+def make_gaussians(cluster_n, img_size):
+    points = []
+    ref_distrs = []
+    for _ in xrange(cluster_n):
+        mean = (0.1 + 0.8*random.rand(2)) * img_size
+        a = (random.rand(2, 2)-0.5)*img_size*0.1
+        cov = np.dot(a.T, a) + img_size*0.05*np.eye(2)
+        n = 100 + random.randint(900)
+        pts = random.multivariate_normal(mean, cov, n)
+        points.append( pts )
+        ref_distrs.append( (mean, cov) )
+    points = np.float32( np.vstack(points) )
+    return points, ref_distrs
+
+from tests_common import NewOpenCVTests
+
+class gaussian_mix_test(NewOpenCVTests):
+
+    def test_gaussian_mix(self):
+
+        np.random.seed(10)
+        cluster_n = 5
+        img_size = 512
+
+        points, ref_distrs = make_gaussians(cluster_n, img_size)
+
+        em = cv.ml.EM_create()
+        em.setClustersNumber(cluster_n)
+        em.setCovarianceMatrixType(cv.ml.EM_COV_MAT_GENERIC)
+        em.trainEM(points)
+        means = em.getMeans()
+        covs = em.getCovs()  # Known bug: https://github.com/opencv/opencv/pull/4232
+        #found_distrs = zip(means, covs)
+
+        matches_count = 0
+
+        meanEps = 0.05
+        covEps = 0.1
+
+        for i in range(cluster_n):
+            for j in range(cluster_n):
+                if (cv.norm(means[i] - ref_distrs[j][0], cv.NORM_L2) / cv.norm(ref_distrs[j][0], cv.NORM_L2) < meanEps and
+                    cv.norm(covs[i] - ref_distrs[j][1], cv.NORM_L2) / cv.norm(ref_distrs[j][1], cv.NORM_L2) < covEps):
+                    matches_count += 1
+
+        self.assertEqual(matches_count, cluster_n)
+
+
+if __name__ == '__main__':
+    NewOpenCVTests.bootstrap()