bring back resolvconf and unbound DNS

bd9c664b1a tried to remove it and use
the system resolver. However, we found that debian has a quirk that it adds
it adds the fqdn as 127.0.1.1. This means that the docker containers
resolve the my.example.com domain to that and can't connect.

This affects any apps doing a turn test (CLOUDRON_TURN/STUN_SERVER)
and also apps like SOGo which use the mail server hostname directly (since
they require proper certs).

https://www.debian.org/doc/manuals/debian-reference/ch05.en.html#_the_hostname_resolution

So, the solution is to go back to unbound, now that port 53 binding is specially
handled anyway in docker.js

src/addons.js

@@ -1200,6 +1200,8 @@ function startMysql(existingInfra, callback) {
                     --log-opt syslog-address=udp://127.0.0.1:2514 \
                     --log-opt syslog-format=rfc5424 \
                     --log-opt tag=mysql \
+                    --dns 172.18.0.1 \
+                    --dns-search=. \
                     -e CLOUDRON_MYSQL_TOKEN=${cloudronToken} \
                     -e CLOUDRON_MYSQL_ROOT_HOST=172.18.0.1 \
                     -e CLOUDRON_MYSQL_ROOT_PASSWORD=${rootPassword} \
@@ -1417,6 +1419,8 @@ function startPostgresql(existingInfra, callback) {
                     --log-opt syslog-address=udp://127.0.0.1:2514 \
                     --log-opt syslog-format=rfc5424 \
                     --log-opt tag=postgresql \
+                    --dns 172.18.0.1 \
+                    --dns-search=. \
                     -e CLOUDRON_POSTGRESQL_ROOT_PASSWORD="${rootPassword}" \
                     -e CLOUDRON_POSTGRESQL_TOKEN="${cloudronToken}" \
                     -v "${dataDir}/postgresql:/var/lib/postgresql" \
@@ -1595,6 +1599,8 @@ function startTurn(existingInfra, callback) {
                 --log-opt tag=turn \
                 -m ${memoryLimit}m \
                 --memory-swap ${memoryLimit * 2}m \
+                --dns 172.18.0.1 \
+                --dns-search=. \
                 -e CLOUDRON_TURN_SECRET="${turnSecret}" \
                 -e CLOUDRON_REALM="${realm}" \
                 --label isCloudronManaged=true \
@@ -1633,6 +1639,8 @@ function startMongodb(existingInfra, callback) {
                     --log-opt syslog-address=udp://127.0.0.1:2514 \
                     --log-opt syslog-format=rfc5424 \
                     --log-opt tag=mongodb \
+                    --dns 172.18.0.1 \
+                    --dns-search=. \
                     -e CLOUDRON_MONGODB_ROOT_PASSWORD="${rootPassword}" \
                     -e CLOUDRON_MONGODB_TOKEN="${cloudronToken}" \
                     -v "${dataDir}/mongodb:/var/lib/mongodb" \
@@ -1859,6 +1867,8 @@ function setupRedis(app, options, callback) {
                     --log-opt tag="${redisName}" \
                     -m ${memoryLimit/2} \
                     --memory-swap ${memoryLimit} \
+                    --dns 172.18.0.1 \
+                    --dns-search=. \
                     -e CLOUDRON_REDIS_PASSWORD="${redisPassword}" \
                     -e CLOUDRON_REDIS_TOKEN="${redisServiceToken}" \
                     -v "${paths.PLATFORM_DATA_DIR}/redis/${app.id}:/var/lib/redis" \