implemented storing of data entered into a task form in localstore

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

frontend/src/Components/MarkdownEditor.svelte

@@ -6,6 +6,7 @@
     let {
         editable = true,
         onclick  = evt => {},
+        onRender = src => {},
         onSet    = newVal => {return true;},
         simple   = false,
         type     = 'div',
@@ -50,6 +51,7 @@
             body       : editValue.source
         });
         editValue.rendered = await resp.text();
+        onRender(editValue.source);
     }
 
     function typed(ev){
@@ -118,4 +120,4 @@
 {:else}
     <svelte:element this={type} {onclick} {oncontextmenu} class={{editable}} title={t('right_click_to_edit')} >{@html target(value.rendered)}</svelte:element>
 {/if}
-</div>
+</div>