Add preference for configuring sticky navbar

Fixes #1354

src/routes/router_utils.nim

@@ -17,13 +17,8 @@ template cookiePrefs*(): untyped {.dirty.} =
 template cookiePref*(pref): untyped {.dirty.} =
   getPref(cookies(request), pref)
 
-template themePrefs*(): Prefs =
-  var res = defaultPrefs
-  res.theme = cookiePref(theme)
-  res
-
 template showError*(error: string; cfg: Config): string =
-  renderMain(renderError(error), request, cfg, themePrefs(), "Error")
+  renderMain(renderError(error), request, cfg, cookiePrefs(), "Error")
 
 template getPath*(): untyped {.dirty.} =
   $(parseUri(request.path) ? filterParams(request.params))

src/routes/unsupported.nim

@@ -10,7 +10,7 @@ export feature
 proc createUnsupportedRouter*(cfg: Config) =
   router unsupported:
     template feature {.dirty.} =
-      resp renderMain(renderFeature(), request, cfg, themePrefs())
+      resp renderMain(renderFeature(), request, cfg, cookiePrefs())
 
     get "/about/feature": feature()
     get "/login/?@i?": feature()