Belatedly add the Portmgr's charter that core@ approved in November
2001 and published to developers@ and ports@ to the internal handbook.
Portmgr has been operating under this charter since then, but people
were having problems finding this in the email archives. Add it to
our internal page so that people no longer have this problem.
I'll also note that core.2 intended to give a very borad range of
powers to portmgr@ to manage the ports tree, while retaining the
ability to clarify and refine the charter over time.