Add Dockerfile for Ascend NPU backend.

Usage:

0. Install Ascend driver on host.
   (https://www.hiascend.com/en/hardware/firmware-drivers)

1. Run docker container.
docker run -it \
   --name opencv \
   --device /dev/davinci0 \
   --device /dev/davinci_manager \
   --device /dev/devmm_svm \
   --device /dev/hisi_hdc \
   -v /usr/local/dcmi:/usr/local/dcmi \
   -v /usr/local/bin/npu-smi:/usr/local/bin/npu-smi \
   -v /usr/local/Ascend/driver/lib64/:/usr/local/Ascend/driver/lib64/ \
   opencv bash

2. Check environment.
npu-smi info

3. Compile opencv with Ascend NPU backend.
cmake -DWITH_CANN=1

4. Run opencv_test_cannops.
./bin/opencv_test_cannops

Author: hipudding

modules/cannops/Dockerfile

@@ -0,0 +1,77 @@
+# User guides
+#
+# 0. Install Ascend driver on host.
+#    (https://www.hiascend.com/en/hardware/firmware-drivers)
+#
+# 1. Run docker container.
+# docker run -it \
+#    --name opencv \
+#    --device /dev/davinci0 \
+#    --device /dev/davinci_manager \
+#    --device /dev/devmm_svm \
+#    --device /dev/hisi_hdc \
+#    -v /usr/local/dcmi:/usr/local/dcmi \
+#    -v /usr/local/bin/npu-smi:/usr/local/bin/npu-smi \
+#    -v /usr/local/Ascend/driver/lib64/:/usr/local/Ascend/driver/lib64/ \
+#    opencv bash
+#
+# 2. Check environment.
+# npu-smi info
+#
+# 3. Compile opencv with Ascend NPU backend.
+# cmake -DWITH_CANN=1
+#
+# 4. Run opencv_test_cannops.
+# ./bin/opencv_test_cannops
+
+FROM ubuntu:20.04
+
+RUN apt update && \
+    DEBIAN_FRONTEND=noninteractive apt install -y \
+    git \
+    wget \
+    gcc \
+    g++ \
+    cmake \
+    make \
+    zlib1g \
+    zlib1g-dev \
+    openssl \
+    libsqlite3-dev \
+    libssl-dev \
+    libffi-dev \
+    unzip \
+    pciutils \
+    net-tools \
+    libblas-dev \
+    gfortran \
+    patchelf \
+    libblas3 && \
+    rm -rf /var/lib/apt/lists/*
+
+# Install Python 3.9
+RUN wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -O ~/miniconda.sh && \
+    bash ~/miniconda.sh -b -p /root/miniconda && \
+    rm -f ~/miniconda.sh
+RUN /root/miniconda/bin/conda create --name opencv -y python=3.9
+ENV PATH=/root/miniconda/envs/opencv/bin/:$PATH
+RUN pip install numpy sympy decorator scipy attrs
+
+# Install CANN
+ENV LD_LIBRARY_PATH=/usr/local/Ascend/driver/lib64/common/:/usr/local/Ascend/driver/lib64/driver/:$LD_LIBRARY_PATH \
+    CANN_TOOLKIT_URL=https://ascend-repo.obs.cn-east-2.myhuaweicloud.com/Milan-ASL/Milan-ASL%20V100R001C13SPC702/Ascend-cann-toolkit_7.0.RC1.alpha002_linux-x86_64.run
+
+RUN wget ${CANN_TOOLKIT_URL} && \
+    chmod +x Ascend-cann-toolkit_7.0.RC1.alpha002_linux-x86_64.run && \
+    ./Ascend-cann-toolkit_7.0.RC1.alpha002_linux-x86_64.run --install && \
+    rm -f ./Ascend-cann-toolkit_7.0.RC1.alpha002_linux-x86_64.run
+
+ENV LD_LIBRARY_PATH=/usr/local/Ascend/driver/lib64:/usr/local/Ascend/driver/lib64/common:/usr/local/Ascend/driver/lib64/driver:$LD_LIBRARY_PATH:/usr/lib64
+ENV ASCEND_TOOLKIT_HOME=/usr/local/Ascend/ascend-toolkit/latest
+ENV LD_LIBRARY_PATH=${ASCEND_TOOLKIT_HOME}/lib64:${ASCEND_TOOLKIT_HOME}/lib64/plugin/opskernel:${ASCEND_TOOLKIT_HOME}/lib64/plugin/nnengine:${ASCEND_TOOLKIT_HOME}/opp/built-in/op_impl/ai_core/tbe/op_tiling:$LD_LIBRARY_PATH
+ENV PYTHONPATH=${ASCEND_TOOLKIT_HOME}/python/site-packages:${ASCEND_TOOLKIT_HOME}/opp/built-in/op_impl/ai_core/tbe:$PYTHONPATH
+ENV PATH=${ASCEND_TOOLKIT_HOME}/bin:${ASCEND_TOOLKIT_HOME}/compiler/ccec_compiler/bin:$PATH
+ENV ASCEND_AICPU_PATH=${ASCEND_TOOLKIT_HOME}
+ENV ASCEND_OPP_PATH=${ASCEND_TOOLKIT_HOME}/opp
+ENV TOOLCHAIN_HOME=${ASCEND_TOOLKIT_HOME}/toolkit
+ENV ASCEND_HOME_PATH=${ASCEND_TOOLKIT_HOME}