chore(edit-docs): move Markdown documentation outside src for now

docs/User Guide/User Guide/Advanced Usage/Advanced Showcases/Task Manager.md

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+# Task Manager
+Task Manager is a [promoted attributes](../Attributes/Promoted%20Attributes.md) and [scripts](../Code%20Notes/Scripts.md)showcase present in the [demo notes](../Database.md).
+
+## Demo
+
+![](../../Attachments/task-manager.png)
+
+Task Manager manages outstanding (TODO) tasks and finished tasks (non-empty doneDate attribute). Outstanding tasks are further categorized by location and arbitrary tags - whenever you change tag attribute in the task note, this task is then automatically moved to appropriate location.
+
+Task Manager also integrates with [day notes](Day%20Notes.md) - notes are [cloned](../../Basic%20Concepts/Note/Cloning%20Notes.md) into day note to both todoDate note and doneDate note (with [prefix](../../Basic%20Concepts/Navigation/Tree%20Concepts.md) of either "TODO" or "DONE").
+
+## Implementation
+
+New tasks are created in the TODO note which has `~child:template` [relation](../Attributes.md)(see [attribute inheritance](../Attributes/Attribute%20Inheritance.md)) pointing to the task template.
+
+### Attributes
+
+Task template defines several [promoted attributes](../Attributes/Promoted%20Attributes.md) - todoDate, doneDate, tags, location. Importantly it also defines `~runOnAttributeChange` relation - [event](../Code%20Notes/Events.md) handler which is run on attribute change. This [script](../Code%20Notes/Scripts.md) handles when e.g. we fill out the doneDate attribute - meaning the task is done and should be moved to "Done" note and removed from TODO, locations and tags.
+
+### New task button
+
+There's also "button" note which contains simple script which adds a button to create new note (task) in the TODO note.
+
+```
+api.addButtonToToolbar({
+    title: 'New task',
+    icon: 'check',
+    shortcut: 'alt+n',
+    action: async () => {
+        // creating notes is backend (server) responsibility so we need to pass
+        // the control there
+        const taskNoteId = await api.runOnBackend(async () => {
+            const todoRootNote = await api.getNoteWithLabel('taskTodoRoot');
+            const {note} = await api.createNote(todoRootNote.noteId, 'new task', '');
+
+            return note.noteId;
+        });
+
+        // we got an ID of newly created note and we want to immediatelly display it
+        await api.activateNewNote(taskNoteId);
+    }
+});
+```
+
+### CSS
+
+In the demo screenshot above you may notice that TODO tasks are in red color and DONE tasks are green.
+
+This is done by having this CSS [code note](../Code%20Notes.md) which defines extra CSS classes:
+
+```
+span.fancytree-node.todo .fancytree-title {
+    color: red !important;
+}
+
+span.fancytree-node.done .fancytree-title {
+    color: green !important;
+}
+```
+
+This [code note](../Code%20Notes.md) has `#appCss` [label](../Attributes.md)which is recognized by Trilium on startup and loaded as CSS into the application.
+
+Second part of this functionality is based in event handler described above which assigns `#cssClass` label to the task to either "done" or "todo" based on the task status.