Deprecate "UNO R4" category

The subcategories of the "Official Hardware" category are to be organized under a subcategory for each of the product
classes. These product classes are defined by the hardware documentation home page.

That hardware documentation places the UNO R4 boards under products under a class named "Classic".

The child categories for each of the boards have already been moved to the appropriate "Classic" parent category. The
category was purely a container, it no longer contains any posts.

This is an interim measure until we can set up a redirect from the "UNO R4" category URL to the "Classic" category in
order to avoid breaking any links. Once that is done, the "UNO R4" category will be deleted.

Author: per1234

content/categories/official-hardware/uno-r4/README.md renamed to content/categories/forum-2005-2010-read-only/uno-r4/README.md

@@ -8,4 +8,4 @@
 
 ## Published At
 
-https://forum.arduino.cc/c/official-hardware/uno-r4/185
+https://forum.arduino.cc/c/forum-2005-2010-read-only/official-hardware/uno-r4/185

content/categories/forum-2005-2010-read-only/uno-r4/_pins.md

@@ -0,0 +1 @@
+- https://forum.arduino.cc/t/about-the-uno-r4-category/1114082

content/categories/forum-2005-2010-read-only/uno-r4/_topics/about-the-uno-r4-category/1.md

@@ -0,0 +1,6 @@
+This category is no longer in use
+
+Please use the dedicated categories for the individual UNO R4 board models:
+
+- #classic:uno-r4-minima
+- #classic:uno-r4-wifi

content/categories/official-hardware/uno-r4/_topics/about-the-uno-r4-category/README.md renamed to content/categories/forum-2005-2010-read-only/uno-r4/_topics/about-the-uno-r4-category/README.md

@@ -86,7 +86,6 @@
     - Nicla Vision
     - Nicla Voice
   - Opta
-  - UNO R4
   - Yún Shield
 - Other Hardware
   - 3rd Party Boards
@@ -174,6 +173,7 @@
   - Emergency Response: Remote Learning
   - India
   - Projects Discussion and Showcase
+  - UNO R4
   - Workshops and Events
     - Makers
     - Events and Tour