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/sioyek/keys_user.config

@@ -0,0 +1,44 @@
+noop <C-w>
+noop q
+close_window q
+
+open_document_embedded o
+
+toggle_custom_color <C-r>
+toggle_two_page_mode d
+
+#goto_begining gg
+goto_end G
+
+screen_up <C-u>
+screen_down <C-d>
+previous_page <C-b>
+next_page <C-f>
+
+next_state {
+prev_state }
+move_down j
+move_up k
+move_left l
+move_right h
+
+fit_to_page_width S
+fit_to_page_width_smart s
+fit_to_page_height a
+fit_to_page_height_smart A
+
+embed_annotations <C-s>
+
+toggle_statusbar <C-n>
+
+regex_search /
+copy y
+rotate_clockwise R
+
+keyboard_select;add_highlight_with_current_type V
+add_highlight H
+
+goto_prev_highlight [h
+goto_next_highlight ]h
+
+goto_mark '

writing/sioyek/prefs_user.config

@@ -0,0 +1,15 @@
+# START FLAVOURS
+
+# END FLAVOURS
+
+super_fast_search 1
+
+should_launch_new_instance 1 # seems to not be working?
+should_launch_new_window 1
+should_load_tutorial_when_no_other_file 0
+check_for_updates_on_startup 0
+should_highlight_unselected_search 1
+
+startup_commands toggle_custom_color
+
+case_sensitive_search 0