feat: add notmuch count module

Displays the result of a notmuch count query
default : unread emails wich path do not contained "Trash" (notmuch count "tag:unread AND NOT path:/.*Trash.*/")

Parameters:
    notmuch_count.query: notmuch count query to show result

Errors:
    if the notmuch query failed, the shown value is  -1

Dependencies:
    notmuch (https://notmuchmail.org/)

themes/icons/awesome-fonts.json

@@ -15,6 +15,9 @@
 	"load": { "prefix": "" },
 	"layout": { "prefix": "" },
 	"layout-xkb": { "prefix": "" },
+	"notmuch_count": { "empty": {"prefix": "\uf0e0" },
+	"items": {"prefix": "\uf0e0" }
+	},
 	"todo": { "empty": {"prefix": "" },
 	"items": {"prefix": "" },
 	"uptime": {"prefix": "" }