Add the slug to the form in the campsite type public page

The idea is that the booking form will be prefilled with the values
passed from that other mini-form, and the campsite type is implicit
due to the page where the form is located at, but i need to give it to
the booking page.

The booking page does not yet use that information.

pkg/campsite/types/public.go

@@ -61,6 +61,7 @@ func (h *PublicHandler) Handler(user *auth.User, company *auth.Company, conn *da
 
 type publicPage struct {
 	*template.PublicPage
+	Slug        string
 	Name        string
 	Carousel    []*carousel.Slide
 	Prices      []*typePrice
@@ -101,6 +102,7 @@ func newPublicPage(ctx context.Context, company *auth.Company, conn *database.Co
 	}
 	page := &publicPage{
 		PublicPage: template.NewPublicPage(),
+		Slug:       slug,
 		Carousel:   mustCollectSlides(ctx, conn, loc, slug),
 		Calendar:   calendar,
 		Prices:     prices,

web/templates/public/campsite/type.gohtml

@@ -35,6 +35,7 @@
 
     <div class="campsite_type_booking">
         <form action="/{{ currentLocale }}/booking" method="get">
+            <input type="hidden" name="type" value="{{ .Slug }}">
             <fieldset>
                 <label>
                     {{( pgettext "Check-in Date" "input")}}