docs: remove webmaster article

This article is out-of-date, so let's instead forward to the "About
Mesa3D.org" article on the main website. This explains where to submit
merge requests for wanted changes.

Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6862>

docs/_exts/redirects.py

@@ -2,7 +2,8 @@ import os
 
 redirects = [
     ('llvmpipe', 'gallium/drivers/llvmpipe.html'),
-    ('postprocess', 'gallium/postprocess.html')
+    ('postprocess', 'gallium/postprocess.html'),
+    ('webmaster', 'https://www.mesa3d.org/website/')
 ]
 
 def create_redirect(dst):

docs/contents.rst

@@ -27,7 +27,6 @@
 
    lists
    bugs
-   webmaster
    Mesa/DRI Wiki <https://dri.freedesktop.org/>
 
 .. toctree::

docs/webmaster.rst

@@ -1,8 +0,0 @@
-Webmaster
-=========
-
-If you have problems, edits or additions for this website send them to
-Brian (*brian.e.paul gmail.com*).
-
-Mark Manning made the frame-based layout for the website. Brian's
-modified it a lot since then.