Make resources.rst more useful to non-devs

Reorder the IRC channel listing so #kerberos is first.  (Developers
form a smaller part of our audience for this documentation set.)
Remove some details that are available on the wiki and not of interest
to non-developers.

Add a pointer to the wiki.

Fix minor grammar errors in Archives.

https://github.com/krb5/krb5/commit/4e0d270faad7fabd773cb159b8cb8e03adb19462
Author: Tom Yu <tlyu@mit.edu>
Commit: 4e0d270faad7fabd773cb159b8cb8e03adb19462
Branch: master
 doc/resources.rst |   32 +++++++++++++++-----------------
 1 files changed, 15 insertions(+), 17 deletions(-)