Update URL to https://tuxpaint.org/ everywhere

Also, add other social media accounts to list of places to
announce Tux Paint in RELEASE docs.

Also, list a ton more options missing from default example config file
"src/tuxpaint.conf"

docs/AUTHORS.txt

@@ -4,9 +4,9 @@ Tux Paint - A simple drawing program for children.
 
 Copyright (c) 2002-2022
 Various contributors (see below, and CHANGES.txt)
-http://www.tuxpaint.org/
+https://tuxpaint.org/
 
-June 17, 2002 - October 14, 2022
+June 17, 2002 - December 11, 2022
 
 * Design and Coding:
 

docs/CHANGES.txt

@@ -4,7 +4,7 @@ Tux Paint - A simple drawing program for children.
 
 Copyright (c) 2002-2022
 Various contributors (see below, and AUTHORS.txt)
-http://www.tuxpaint.org/
+https://tuxpaint.org/
 
 
 2022.December.9 (0.9.29)

docs/RELEASE.txt

@@ -110,16 +110,16 @@ Time to release:
 
 Website updates
 ---------------
- * List new features on http://www.tuxpaint.org/features/
+ * List new features on https://tuxpaint.org/features/
 
- * Add any new requirements to http://www.tuxpaint.org/requirements/
+ * Add any new requirements to https://tuxpaint.org/requirements/
 
 Announcements
 -------------
  * Managed by Tux Paint
 
    + Tux Paint website
-     - Site: http://www.tuxpaint.org/
+     - Site: https://tuxpaint.org/
      - Submissions: [add announcement to /latest/]
 
    + Tux Paint on Facebook
@@ -130,6 +130,22 @@ Announcements
      - Site: https://www.facebook.com/TuxPaint
      - Submissions: [currently managed by Bill K.]
 
+   + Tux Paint on Tumblr
+     - Site: https://www.tumblr.com/blog/tuxpaint
+     - Submissions: [currently managed by Bill K.]
+
+   + Tux Paint on Reddit
+     - https://www.reddit.com/user/TuxPaintDevs
+     - Submissions: [currently managed by Bill K.]
+
+   + Tux Paint on Mastodon
+     - https://floss.social/@tuxpaint
+     - Submissions: [currently managed by Bill K.]
+
+   + Tux Paint on Instagram
+     - https://www.instagram.com/tuxpaintdevs/
+     - Submissions: [currently managed by Bill K.]
+
  * News sites & magazines
 
    + Linux Today