Add 'always hide CC drawer' option

When the CC starts up, it opens the drawer by default. The option
introduced by this commit closes it as soon as the content script gets
injected into the page.

Feature suggested at pekb/thread/67965396?msgid=69642485

Fixes: #10
Change-Id: I2a043dc9888eee2c9b1f98713d36cd1a49d3c931
diff --git a/src/_locales/es/messages.json b/src/_locales/es/messages.json
index 00d4a60..61156c7 100644
--- a/src/_locales/es/messages.json
+++ b/src/_locales/es/messages.json
@@ -75,6 +75,10 @@
     "message": "la configuración del modo oscuro del SO",
     "description": "Select option added in #ccdarktheme_mode--container, in the options_ccdarktheme string"
+  "options_ccforcehidedrawer": {
+    "message": "Esconde siempre la barra lateral izquierda en la Consola de la Comunidad.",
+    "description": "Feature checkbox in the options page"
+  },
   "options_profileindicator_header": {
     "message": "Punto indicador",
     "description": "Heading for the profile indicator feature options"