Add Dockerfile for server & studio (#845)

1. Add hosts to speed up image download
2. Modify some configs to enable the server to run better in container
3. Because Dockerfile doesn't allow multiple startup commands, currently only the server will be automatically started after the container is started. If you want to start studio, you can enter the container to start it.

Here is a simple container start command:
```bash
docker run -it --name=graph -p 18080:8080 -p 18088:8088 hugegraph:0.10 /bin/bash
```

1. Github-IP is not fixed, comment it now
2. For the convenience of users, the apt-source is not cleared by default.

Dockerfile

@@ -0,0 +1,51 @@
+FROM ubuntu:xenial
+
+LABEL maintainer="HugeGraph Docker Maintainers <hugegraph@googlegroups.com>"
+
+ENV PKG_URL https://github.com/hugegraph
+
+# 1. Install needed dependencies of GraphServer & RocksDB
+RUN set -x \
+    && apt-get -q update \
+    && apt-get -q install -y --no-install-recommends --no-install-suggests \
+       curl \
+       lsof \
+       g++ \
+       gcc \
+       openjdk-8-jdk \
+    && apt-get clean
+    # && rm -rf /var/lib/apt/lists/*
+
+# 2. Init HugeGraph Sever
+# (Optional) You can set the ip of github to speed up the local build
+# && echo "192.30.253.112 github.com\n151.101.44.249 github.global.ssl.fastly.net" >> /etc/hosts \
+ENV SERVER_VERSION 0.10.4
+RUN set -e \
+    && mkdir -p /root/hugegraph-server \
+    && curl -L -S ${PKG_URL}/hugegraph/releases/download/v${SERVER_VERSION}/hugegraph-${SERVER_VERSION}.tar.gz -o /root/server.tar.gz \
+    && tar xzf /root/server.tar.gz --strip-components 1 -C /root/hugegraph-server \
+    && rm /root/server.tar.gz \
+    && cd /root/hugegraph-server/ \
+    && sed -i "s/^restserver.url.*$/restserver.url=http:\/\/0.0.0.0:8080/g" ./conf/rest-server.properties \
+    && sed -n '63p' ./bin/start-hugegraph.sh | grep "&" > /dev/null && sed -i 63{s/\&$/#/g} ./bin/start-hugegraph.sh \
+    && sed -n '74p' ./bin/start-hugegraph.sh | grep "exit" > /dev/null && sed -i 74{s/^/#/g} ./bin/start-hugegraph.sh \
+    && ./bin/init-store.sh
+
+# 3. Prepare for HugeGraph Studio
+ENV STUDIO_VERSION 0.10.0
+# (Optional) You can set the ip of github to speed up the local build
+# && echo "192.30.253.112 github.com\n151.101.44.249 github.global.ssl.fastly.net" >> /etc/hosts \
+RUN set -e \
+    && mkdir -p /root/hugegraph-studio \
+    && curl -L -S ${PKG_URL}/hugegraph-studio/releases/download/v${STUDIO_VERSION}/hugegraph-studio-${STUDIO_VERSION}.tar.gz -o /root/studio.tar.gz \
+    && tar xzf /root/studio.tar.gz --strip-components 1 -C /root/hugegraph-studio \
+    && rm /root/studio.tar.gz \
+    && cd /root/hugegraph-studio/ \
+    && sed -i "s/^studio.server.host.*$/studio.server.host=0.0.0.0/g" ./conf/hugegraph-studio.properties \
+    && sed -i "s/^graph.server.host.*$/graph.server.host=0.0.0.0/g" ./conf/hugegraph-studio.properties
+
+EXPOSE 8080 8088
+WORKDIR /root
+VOLUME /root
+
+ENTRYPOINT ["./hugegraph-server/bin/start-hugegraph.sh"]