writing: Restructure module layout per-program

Similarly to the qutebrowser module we change the layout to have a
program name at the top-level and all required files for that specific
program within, whether they reside within .config, .local or anywhere
else.
We use dotter mappings to achieve this.

writing/jrnl/jrnl.yaml

@@ -0,0 +1,19 @@
+colors:
+  body: none
+  date: none
+  tags: none
+  title: none
+default_hour: 9
+default_minute: 0
+editor: nvim
+encrypt: false
+highlight: true
+indent_character: '|'
+journals:
+  default:
+    journal: ~/documents/records/jrnl.md
+linewrap: 79
+tagsymbols: '+'
+template: false
+timeformat: '%F %r'
+version: v4.1