portal: implement RemoteDesktop portal

wire/jay_compositor.txt

@@ -88,6 +88,10 @@ request select_workspace {
     seat: id(wl_seat),
 }
 
+request create_ei_session (since = 5) {
+    id: id(jay_ei_session_builder),
+}
+
 # events
 
 event client_id {

wire/jay_ei_session.txt

@@ -0,0 +1,15 @@
+request release (since = 5) {
+
+}
+
+event destroyed (since = 5) {
+
+}
+
+event created (since = 5) {
+    fd: fd,
+}
+
+event failed (since = 5) {
+    reason: str,
+}

wire/jay_ei_session_builder.txt

@@ -0,0 +1,7 @@
+request commit (since = 5) {
+    id: id(jay_ei_session),
+}
+
+request set_app_id (since = 5) {
+    app_id: str,
+}