Move librecovery_ui to a sub-directory

This helps to expose librecovery_ui for device specific RecoveryUi.

Bug: 76436783
Test: mma, unit tests pass
Change-Id: Ic6c3d301d5833e4a592e6ea9d9d059bc4e4919be

install.cpp

@@ -53,8 +53,8 @@
 #include "otautil/thermalutil.h"
 #include "package.h"
 #include "private/install.h"
+#include "recovery_ui/ui.h"
 #include "roots.h"
-#include "ui.h"
 #include "verifier.h"
 
 using namespace std::chrono_literals;