Prepare api directory for udc mainline branch

udc-extended-api directory will be used only in udc mainline branch to
hide @FlaggedApi annotated api which is not supported in that branch

Copied api directories from udc mainline branch.

Bug: 299411828
Test: TH
Change-Id: I86023b1fb3e5f9b4b787a564303e6d2e60f74467
diff --git a/framework-t/udc-extended-api/system-lint-baseline.txt b/framework-t/udc-extended-api/system-lint-baseline.txt
new file mode 100644
index 0000000..9baf991
--- /dev/null
+++ b/framework-t/udc-extended-api/system-lint-baseline.txt
@@ -0,0 +1,7 @@
+// Baseline format: 1.0
+BuilderSetStyle: android.net.IpSecTransform.Builder#buildTunnelModeTransform(java.net.InetAddress, android.net.IpSecManager.SecurityParameterIndex):
+    Builder methods names should use setFoo() / addFoo() / clearFoo() style: method android.net.IpSecTransform.Builder.buildTunnelModeTransform(java.net.InetAddress,android.net.IpSecManager.SecurityParameterIndex)
+
+
+GenericException: android.net.IpSecManager.IpSecTunnelInterface#finalize():
+    Methods must not throw generic exceptions (`java.lang.Throwable`)