wayland: implement virtual-keyboard

wire/zwp_virtual_keyboard_manager_v1.txt

@@ -0,0 +1,4 @@
+request create_virtual_keyboard {
+    seat: id(wl_seat),
+    id: id(zwp_virtual_keyboard_v1),
+}

wire/zwp_virtual_keyboard_v1.txt

@@ -0,0 +1,21 @@
+request keymap {
+    format: u32,
+    fd: fd,
+    size: u32,
+}
+
+request key {
+    time: u32,
+    key: u32,
+    state: u32,
+}
+
+request modifiers {
+    mods_depressed: u32,
+    mods_latched: u32,
+    mods_locked: u32,
+    group: u32,
+}
+
+request destroy {
+}