Add Kill Switch section

Currently there's a nasty bug which doesn't allow users from navigating
from the "Kill Switch" section to any other section of the app (see bug
twpowertools:59), but everything else is working.

Change-Id: I3c71352b1899e4ddf9ba5886aa1434a5a1ed93eb
diff --git a/frontend/src/theme.scss b/frontend/src/theme.scss
index 0c4e5a8..c0d06ac 100644
--- a/frontend/src/theme.scss
+++ b/frontend/src/theme.scss
@@ -20,6 +20,7 @@
 @use "@material/notched-outline/mdc-notched-outline";
 @use "@material/textfield";
 @use "@material/select/styles" as b-style; // https://github.com/sass/sass/issues/2778#issuecomment-558365532
+@use "@material/form-field";
 
 @include drawer.core-styles;
 @include drawer.dismissible-core-styles;
@@ -32,6 +33,8 @@
 @include dialog.core-styles;
 @include fab.core-styles;
 @include textfield.core-styles;
+@include checkbox.core-styles;
+@include form-field.core-styles;
 
 html {
   height: 100%;