web: use Python 3 only for certbot

certbot-auto will install both Python 2 and 3 packages thus resulting un
unnecessary image bloat. Also, there is no need to install compilers or
development libraries since Wheels are available for the required
packags.

web/Dockerfile

@@ -7,18 +7,18 @@ COPY rootfs/ /
 
 RUN \
 	apt-dpkg-wrap apt-get update && \
-	apt-dpkg-wrap apt-get install -y cron nginx-extras jitsi-meet-web && \
+	apt-dpkg-wrap apt-get install -y cron nginx-extras jitsi-meet-web python3-venv && \
 	apt-dpkg-wrap apt-get -d install -y jitsi-meet-web-config && \
     dpkg -x /var/cache/apt/archives/jitsi-meet-web-config*.deb /tmp/pkg && \
     mv /tmp/pkg/usr/share/jitsi-meet-web-config/config.js /defaults && \
 	mv /usr/share/jitsi-meet/interface_config.js /defaults && \
-	apt-cleanup && \
 	rm -f /etc/nginx/conf.d/default.conf && \
+	apt-cleanup && \
 	rm -rf /tmp/pkg /var/cache/apt
 
 RUN \
 	chmod a+x /usr/local/bin/certbot-auto && \
-	certbot-auto --noninteractive --install-only
+	USE_PYTHON_3=1 certbot-auto --noninteractive --install-only --no-bootstrap
 
 EXPOSE 80 443