Remove unused vendor overlays, dongle/peripheral shields, and steno config

Stripped to corne_left + corne_right on nice_nano_v2 only.

config/west.yml

@@ -11,12 +11,6 @@ manifest:
     # fork of zmk-nice-oled with custom KM medal animation
     - name: KeebMaker
       url-base: https://github.com/KeebMaker
-    # javelin steno engine module
-    - name: afiqzudinhadi
-      url-base: https://github.com/afiqzudinhadi
-    # javelin steno engine source
-    - name: jthlim
-      url-base: https://github.com/jthlim
   projects:
     # Pinned to v0.3.0 instead of `main`: ZMK main tracks Zephyr 4.1, whose
     # board-model rewrite renamed `nice_nano_v2` (now `nice_nano//zmk`) and
@@ -42,14 +36,5 @@ manifest:
     - name: zmk-oled-adapter
       remote: mctechnology17
       revision: main
-    # javelin steno engine module
-    - name: zmk-javelin-steno
-      remote: afiqzudinhadi
-      revision: main
-    # javelin steno engine source (fetched into module's javelin/ dir)
-    - name: javelin-steno
-      remote: jthlim
-      revision: main
-      path: zmk-javelin-steno/javelin
   self:
     path: config