Implement empty-workspace-above-first (#745)

* Implement empty-workspace-above-first option

* add two failing tests

* fix interactive_move_onto_empty_output_ewaf and
interactive_move_onto_first_empty_workspace tests

* Add two failing ewaf option toggle tests

* Fix adding/removing first empty workspace on option toggle

* Don't remove first empty workspace if focused

* Stop workspace switch when enabling ewaf

* layout/monitor: Offset workspace switch on adding workspace above

* Fix some initial active workspace ids with ewaf

* wiki: Document empty-workspace-above-first

---------

Co-authored-by: Ivan Molodetskikh <yalterz@gmail.com>

wiki/Configuration:-Layout.md

@@ -9,6 +9,7 @@ layout {
     gaps 16
     center-focused-column "never"
     always-center-single-column
+    empty-workspace-above-first
 
     preset-column-widths {
         proportion 0.33333
@@ -100,6 +101,18 @@ layout {
 }
 ```
 
+### `empty-workspace-above-first`
+
+<sup>Since: 0.1.11</sup>
+
+If set, niri will always add an empty workspace at the very start, in addition to the empty workspace at the very end.
+
+```kdl
+layout {
+    empty-workspace-above-first
+}
+```
+
 ### `preset-column-widths`
 
 Set the widths that the `switch-preset-column-width` action (Mod+R) toggles between.