reference: remove deprecated SDK and replace category page

- Remove references to the deprecated Golioth Zephyr SDK.
- Replace "Device SDKs" category the Golioth Firmware SDK page.

Signed-off-by: Mike Szczys <mike@golioth.io>

Author: szczys

docs/reference/1-home.md

@@ -12,7 +12,5 @@ and advanced platform features.
 - Command Line Tools
   - [goliothctl](/reference/command-line-tools/goliothctl/goliothctl/)
   - [coap](/reference/command-line-tools/coap/coap/)
-- Device SDKs
-  - [Golioth Firmware SDK Reference](/reference/device-sdks/golioth-firmware-sdk)
-  - [Golioth Zephyr SDK Reference](/reference/device-sdks/golioth-zephyr-sdk)
+- Device SDK: [Golioth Firmware SDK Reference](/reference/golioth-firmware-sdk)
 - [Billing](/reference/billing)

docs/reference/5-device-sdks/2-zephyr-sdk.md

@@ -1,5 +1,4 @@
 ---
-id: golioth-firmware-sdk
 title: Golioth Firmware SDK
 ---
 

docs/reference/5-device-sdks/_category_.yml

@@ -432,6 +432,11 @@
           "source": "/firmware/zephyr-device-sdk{,/**}",
           "destination": "/firmware/golioth-firmware-sdk",
           "type": 301
+        },
+        {
+          "source": "/reference/device-sdks{,/**}",
+          "destination": "/reference/golioth-firmware-sdk",
+          "type": 301
         }
       ],
       "rewrites": [