- remove contradicting instructions to keep subject to one line and at
  the same time wrap at column 72
- git doesn't seem to remove the extra empty line after the subject any
  more, so just insert it and don't be so explict about it
- use "footers" instead of "fields". more intuitive, i think
- add some "docu" to the footer templates
- refer to the commit policy at the bottom

Change-Id: Ic1ee454a9535bc9e16aa716043605f57ca79f444
Sanity-Review: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>
Reviewed-by: Sergio Ahumada <sergio.ahumada@nokia.com>
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>