implemented editing of document in GUI + respective handlers in backend

frontend/src/routes/document/PositionList.svelte

@@ -4,7 +4,7 @@
     import { onMount } from 'svelte';
     import { t } from '../../translations.svelte.js';
 
-    var { document = $bindable(null) } = $props();
+    var { document = $bindable(null), submit = (key,newVal) => {} } = $props();
 
     let editable = $derived(document.state == 1);
 </script>
@@ -25,7 +25,7 @@
     </thead>
     <tbody>
         {#each Object.entries(document.positions) as [id,pos]}
-        <Position currency={document.currency} bind:pos={document.positions[id]} editable={editable} />
+        <Position currency={document.currency} bind:pos={document.positions[id]} editable={editable} {submit} />
         {/each}
         <tr class="sums">
             <td colspan="2"></td>