Doc that autorelease builds come with taglist file, versions of included projects

Add Int/Pack readthedocs docs that describe the taglist file included in ODL distros created by autorelease, and the resulting RPM/Deb packages.

autorelease 88be591565c5103f631bb097f83942bc497c55e7 Boron-SR1
aaa 304660c0f1a12840e3d524e31630fbc173b7d7b5 Boron-SR1
alto a1cc4bf0a930f1dc12f09779dbc78d26711180d1 Boron-SR1
atrium b050d8af7468077bf0edbdaef8d1a5789b2ce70e Boron-SR1
#snip many more

Not that you necessarily need to include this level of detail, but it's created by this logic in autorelease's JJB.

echo autorelease `git rev-parse --verify HEAD` ${RELEASE_TAG} | tee -a $WORKSPACE/taglist.log

git submodule foreach 'echo $path `git rev-parse --verify HEAD` ${RELEASE_TAG} | tee -a $WORKSPACE/taglist.log'

The first does the autorelease line, the next loops to do each project's submodule.

The resulting file is copied to `integration/distribution/distribution-karaf/src/main/assembly/`, which makes its way into resulting distros in the root dir. A user installing an ODL package would see the taglist with the exact versions of each included project at `/opt/opendaylight/taglist.log`.

Imported from Trello