app: migrate to new shim implementation

Both machinectl and sudo launch methods launch shim as shim is now responsible for setting up the sandbox. Various app structures are adapted to accommodate bwrap configuration and mediated wayland access.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

internal/app/app.go

@@ -1,6 +1,7 @@
 package app
 
 import (
+	"net"
 	"os/exec"
 	"sync"
 )
@@ -18,6 +19,8 @@ type app struct {
 	seal *appSeal
 	// underlying fortified child process
 	cmd *exec.Cmd
+	// wayland connection if wayland mediation is enabled
+	wayland *net.UnixConn
 	// error returned waiting for process
 	wait error