front/BaseTemplate: allow disabling header, h1 and footer via boolean attributes

src/assets/views/templates/BaseTemplate.svelte

@@ -8,6 +8,9 @@
     export let h1: string = title;
     export let description: string;
     export let refresh_after: number | undefined = undefined;
+    export let noHeader: boolean = false;
+    export let noH1: boolean = false;
+    export let noFooter: boolean = false;
 </script>
 
 <CommonScripts/>
@@ -46,14 +49,16 @@
     <link rel="stylesheet" href="/css/layout.css">
 </svelte:head>
 
+{#if !noHeader}
     <BaseHeader/>
+{/if}
 
 <div class="flash-messages">
     <FlashMessages/>
 </div>
 
 <main>
-    {#if h1}
+    {#if h1 && !noH1}
         <h1>{h1}</h1>
     {/if}
     {#if $$slots.subtitle}
@@ -64,4 +69,6 @@
     <slot/>
 </main>
 
+{#if !noFooter}
     <BaseFooter/>
+{/if}