categories: add the Cellular Routers category with its corresponding platforms

- This new category containins the following Digi cellular routers platforms:
  · Digi AnywhereUSB 2/8/24 Plus
  · Digi Connect EZ mini/2/4/8/16/32
  · Digi Connect IT mini/4/16/48
  · Digi EX12
  · Digi EX15/EX15W
  · Digi EX50
  · Digi IX10
  · Digi IX20/IX20W
  · Digi IX30
  · Digi IX40
  · Digi LR54/LR54W
  · Digi TX40
  · Digi TX54
  · Digi TX64/TX64-Rail
- The already existing 'XBee Gateways' category remains as is with the
  following XBee gateways platforms:
  · Digi IX15 (XBee Gateway)

Signed-off-by: Diego Escalona <diego.escalona@digi.com>

Author: diescalo

categories/categories.xml

@@ -7,4 +7,12 @@
         <icon>category_gateway.png</icon>
         <icon_selected>category_gateway_selected.png</icon_selected>
     </category>
+    <category id="cellular_router">
+        <name>Cellular Routers</name>
+        <description>Cellular routers and extenders.</description>
+        <project_type>Python</project_type>
+        <dest_path>/etc/config</dest_path>
+        <icon>category_cellular_router.png</icon>
+        <icon_selected>category_cellular_router_selected.png</icon_selected>
+    </category>
 </categories>