add Dockerfile for pica-gchange

pica-gchange/Dockerfile

+FROM registry.picasoft.net/pica-nginx
+LABEL maintainer jeremy.maille@etu.utc.fr
+RUN 	apt-get update && \
+	apt-get install -y zip && \
+	wget --quiet https://github.com/duniter-gchange/gchange-client/releases/download/v0.9.2/gchange-v0.9.2-web.zip -O gchange.zip && \
+	unzip gchange.zip -d /var/www/html && \
+	rm gchange.zip && \
+	apt-get remove -y zip && \
+	rm -r /var/lib/apt/lists/*