all-base-packages: Add debconf and dialog

First installed as dependency for multiple packages and second is used
by debconf, but not installed as it's dependency. This enables package
configuration during install or dpkg-reconfigure(7) from debconf.

This removes following messages on console during package install:

  debconf: unable to initialize frontend: Dialog
  debconf: (No usable dialog-like program is installed, so the dialog \
based frontend cannot be used. at \
/usr/share/perl5/Debconf/FrontEnd/Dialog.pm line 76, <> line 11.)
  debconf: falling back to frontend: Readline

Signed-off-by: Sergey Popovich <sergey.popovich@ordnance.co>

builds/any/rootfs/jessie/common/all-base-packages.yml

@@ -8,6 +8,8 @@
 - python
 - apt
 - apt-utils
+- debconf
+- dialog
 - procps
 - net-tools
 - iputils-ping

builds/any/rootfs/stretch/common/all-base-packages.yml

@@ -8,6 +8,8 @@
 - python
 - apt
 - apt-utils
+- debconf
+- dialog
 - procps
 - net-tools
 - iputils-ping

builds/any/rootfs/wheezy/common/all-base-packages.yml

@@ -7,6 +7,8 @@
 - python
 - apt
 - apt-utils
+- debconf
+- dialog
 - procps
 - net-tools
 - iputils-ping