01_Application_Framework: 01_Introduction.md

This formats the entire page to at most 80 characters wide pagraphs.

Mentions that with 'needlefish' we started using gRPC and that we've
started to deprecate D-Bus, including the fact that we no longer spawn
directly applications, that we use system units for listing
applications. Most the of page is kept intact with those minor changes
being added.

Bug-AGL: SPEC-4700
Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Change-Id: Id19e6cea90fdbe9a6bd4eee851f83b9d0f800db5
(cherry picked from commit 976f309b284792a82db3311ca9b6614564ff4e9c)
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/documentation/+/28537
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>