feat: Change file structure

- Move return object to named export for 11ty config
- screens is now view
- 11ty data files moved to view/_data
- templates is now view/_includes
- Both are the default directories
- data is now used as intended, for user data
- Update index to reflect filenames and structure

source/view/demo/examples/songbook/0_artist-title.md

@@ -0,0 +1,26 @@
+---
+tags: 
+  - songbook
+  - song
+title: "Interpret - Titel"
+releaseDate: JJJJ
+description: Text
+---
+~~~
+[verse 1]
+strophe 1
+
+[chorus]
+refrain
+
+[verse 2]
+strophe 2
+
+[chorus]
+[bridge]
+überleitung
+
+[interlude]
+[chorus]
+[outro]
+~~~