Add input settings, with mouse, keyboard, keyboard shortcuts sub-pages

Still needs to be integrated with compositor so it actually works, need
touchpad page, etc.

app/src/pages/input/mod.rs

@@ -0,0 +1,81 @@
+use cosmic_settings_page as page;
+
+pub mod keyboard;
+mod mouse;
+
+#[derive(Clone, Debug)]
+pub enum Message {
+    SetAcceleration(bool),
+    SetNaturalScroll(bool),
+    SetScrollSpeed(u32),
+    SetDoubleClickSpeed(u32),
+    SetMouseSpeed(u32),
+    PrimaryButtonSelected(cosmic::widget::segmented_button::Entity),
+    // seperate close message, to make sure another isn't closed?
+    ExpandInputSourcePopover(Option<String>),
+    OpenKeyboardShortcuts,
+}
+
+#[derive(derivative::Derivative)]
+#[derivative(Default)]
+pub struct Page {
+    // Mouse
+    #[derivative(Default(value = "mouse::default_primary_button()"))]
+    primary_button: cosmic::widget::segmented_button::SingleSelectModel,
+    acceleration: bool,
+    natural_scroll: bool,
+    double_click_speed: u32,
+    scroll_speed: u32,
+    mouse_speed: u32,
+
+    // Keyboard
+    expanded_source_popover: Option<String>,
+    #[derivative(Default(value = "keyboard::default_input_sources()"))]
+    sources: Vec<keyboard::InputSource>,
+}
+
+impl Page {
+    // TODO
+    pub fn update(&mut self, message: Message) {
+        match message {
+            Message::SetAcceleration(value) => {
+                self.acceleration = value;
+            }
+            Message::SetNaturalScroll(value) => {
+                self.natural_scroll = value;
+            }
+            Message::SetScrollSpeed(value) => {
+                self.scroll_speed = value;
+            }
+            Message::SetDoubleClickSpeed(value) => {
+                self.double_click_speed = value;
+            }
+            Message::SetMouseSpeed(value) => {
+                self.mouse_speed = value;
+            }
+            Message::PrimaryButtonSelected(entity) => {
+                self.primary_button.activate(entity);
+            }
+            Message::ExpandInputSourcePopover(value) => {
+                self.expanded_source_popover = value;
+            }
+            // TODO Specially handled in app.rs
+            Message::OpenKeyboardShortcuts => {}
+        }
+    }
+}
+
+impl page::Page<crate::pages::Message> for Page {
+    fn info(&self) -> page::Info {
+        // XXX icon?
+        page::Info::new("input", "input-keyboard-symbolic")
+            .title(fl!("input"))
+            .description(fl!("input", "desc"))
+    }
+}
+
+impl page::AutoBind<crate::pages::Message> for Page {
+    fn sub_pages(page: page::Insert<crate::pages::Message>) -> page::Insert<crate::pages::Message> {
+        page.sub_page::<keyboard::Page>().sub_page::<mouse::Page>()
+    }
+}