Fluentd: td-agent repository for Debian

Change-Id: I0f05183889971dcc014663a849d3fc1d87a19e8e
(manual picked from commit 2131ef9)

Author: viktormichalek

docker/base/Dockerfile.j2

@@ -355,6 +355,7 @@ COPY apt_preferences.{{ base_distro }} /etc/apt/preferences
       'https://download.docker.com/linux/debian/gpg',
       'https://packages.grafana.com/gpg.key',
       'http://buster-stein.debian.net/debian/dists/pubkey.gpg',
+      'https://packages.treasuredata.com/GPG-KEY-td-agent',
     ] %}
     {% set base_apt_packages = base_apt_packages +
       ['sudo',]

docker/base/sources.list.debian

@@ -15,3 +15,6 @@ deb https://download.docker.com/linux/debian buster stable
 # Buster - Stein repos
 deb http://buster-stein.debian.net/debian buster-stein-backports main
 deb http://buster-stein.debian.net/debian buster-stein-backports-nochange main
+
+# td-agent for fluentd
+deb http://packages.treasuredata.com/3/debian/stretch stretch contrib