Make screenshot path configurable

resources/default-config.kdl

@@ -110,6 +110,13 @@ preset-column-widths {
 // Set gaps around windows in logical pixels.
 gaps 16
 
+// You can change the path where screenshots are saved.
+// A ~ at the front will be expanded to the home directory.
+screenshot-path "~/Pictures/Screenshots"
+
+// You can also set this to null to disable saving screenshots to disk.
+// screenshot-path null
+
 binds {
     // Keys consist of modifiers separated by + signs, followed by an XKB key name
     // in the end. To find an XKB name for a particular key, you may use a program