Delete sn-nord-theme.yaml

Removes marc-sensenich/sn-nord-theme, which was not building correctly, in favour of my own nord theme.

extensions/sn-nord-theme.yaml

@@ -1,19 +0,0 @@
----
-id: com.marc-sensenich.sn-nord-theme
-github: marc-sensenich/sn-nord-them
-main: theme.css
-
-name: SN Nord Theme
-content_type: SN|Theme
-area: themes
-version: 0.1.8
-marketing_url: https://github.com/marc-sensenich/sn-nord-them
-description: An arctic, north-bluish clean and elegant Standard Notes theme.
-
-statusBar: dark-content
-dock_icon:
-  type: circle
-  background_color: '#88C0D0'
-  foreground_color: '#88C0D0'
-  border_color: '#88C0D0'
-...