apt: Introduce the new terse apt output format 3.0

The key talking points here are:

1. Instead of long sentences, we use short concise messages,
   e.g. "The following NEW packages will be installed" becomes
   "Installing".

2. Dependencies are only listed once. We removed the
   "The following additional packages will be installed" section
   in favor of splitting up the "Installing" section into
   "Installing" and "Installing dependencies" (like dnf)

3. The order of the output is different:

   1. Packages to be installed manually
   2. Packages to be installed automatically
   4. Weak dependencies of new packages not installed
   3. Packages to be upgraded
   4. Packages to be downgraded
   5. Packages that have been kept back / are on hold
   6. Removals
   7. Essential removals

   i.e. we logically show you the action that is being
   done, followed by lists related to the action.

4. As requested by popey, we have colorful UI, with green for
   packages being installed and red for packages being removed.

Caveats:

- The list of recommends and suggests has not been updated yet,
  it should move to after the packages being installed (as they
  are what triggers them)

This also introduces output format versioning, configured by the
APT::Output-Format option. The default value is 0, except for the
apt(8) binary where it is 30 - which enables the new style.

1 files changed, 1 insertions, 0 deletions

diff --git a/doc/examples/configure-index b/doc/examples/configure-index
index a8fc98daa..cc9a2e765 100644
--- a/doc/examples/configure-index
+++ b/doc/examples/configure-index
@@ -723,6 +723,7 @@ apt::system "<STRING>";
 apt::acquire::translation "<STRING>"; // deprecated in favor of Acquire::Languages
 apt::color::highlight "<STRING>";
 apt::color::neutral "<STRING>";
+apt::output-version "<INT>";
 
 dpkgpm::reporting-steps "<INT>";