add vf dockerfiles

Containers/dockerfiles/Ubuntu20_04.Dockerfile

+# VirtualFluids BuildDependencies:
+# Ubuntu 20.04
+# general tools: wget, unzip, git
+# CMake 3.20.5
+# ccache
+# gcc 9.3 (default)
+# openmpi 4.0.3
+# openmp
+# cuda 11.3.1 as base image
+# clang 10.0 (default)
+
+FROM nvidia/cuda:11.3.1-devel-ubuntu20.04
+
+ENV DEBIAN_FRONTEND=noninteractive
+RUN apt-get update &&\
+    apt-get install -y\
+    wget unzip git \
+    build-essential gdb\
+    ccache \
+    ninja-build \
+    openmpi-bin=4.0.3-0ubuntu1 \
+    libomp-dev \
+    clang clang-format clang-tidy clang-tools llvm-dev libclang-dev &&\
+    mkdir -p /usr/local/cmake/ && cd /usr/local/cmake/ &&\
+    version=3.20 && build=5 &&\
+    wget https://cmake.org/files/v$version/cmake-$version.$build-linux-x86_64.tar.gz &&\
+    tar -xzvf cmake-$version.$build-linux-x86_64.tar.gz &&\
+    ln -s /usr/local/cmake/cmake-$version.$build-linux-x86_64/bin/* /usr/local/bin/
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Containers/dockerfiles/Ubuntu20_04_Python.Dockerfile

+FROM irmb/virtualfluids-deps-ubuntu20.04:latest
+
+ENV DEBIAN_FRONTEND=noninteractive
+RUN apt-get update &&    \
+    apt-get install -y   \
+        python3          \
+        python3-venv     \
+        python3-pip      \
+        uuid-dev         \
+        libgpgme-dev     \
+        squashfs-tools   \
+        libseccomp-dev   \
+        pkg-config       \
+        cryptsetup-bin   \
+        golang           \
+        libgl1           \
+    && pip3 install      \
+        setuptools       \
+        wheel            \
+        scikit-build     \
+        pyvista          \
+        numpy            \
+        ansible          \
+    && export VERSION=3.8.0 \
+    && wget https://github.com/sylabs/singularity/releases/download/v${VERSION}/singularity-ce-${VERSION}.tar.gz \
+    && tar -xzf singularity-ce-${VERSION}.tar.gz
+
+WORKDIR /singularity-ce-3.8.0
+RUN ./mconfig && \
+    make -C ./builddir && \
+    make -C ./builddir install
+
+WORKDIR /
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