Add image upload support

Images can be uploaded, thumbnails are created, they're displayed within
the threads themselves. Just like four chans!

There is not an upload size limit set yet. Gotta get on that next.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

threadchat/settings.py

@@ -124,3 +124,11 @@ STATIC_URL = "static/"
 # https://docs.djangoproject.com/en/4.0/ref/settings/#default-auto-field
 
 DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"
+
+# Media root - where media files are stored on the disk
+MEDIA_ROOT = "media/"
+
+# Media URL - the URL where media is served from
+MEDIA_URL = "media/"
+
+THUMB_SIZE = (200, 200)