Add logic to retrieve KS2 certificates in supplicant.

Logic was largely copied from
android.system.wifi.keystore@1.0

Bug: 205764502
Test: Manual test - store a key-value pair to
      legacy Keystore. Check that we can retrieve
      the value in supplicant using the new method.
Change-Id: I8f12e447747f2e1a98e2d37b3453526cdde9e2de
diff --git a/wpa_supplicant/Android.mk b/wpa_supplicant/Android.mk
index 1da9e61..2b798fa 100644
--- a/wpa_supplicant/Android.mk
+++ b/wpa_supplicant/Android.mk
@@ -1813,6 +1813,7 @@
 endif
 ifeq ($(WPA_SUPPLICANT_USE_AIDL), y)
 LOCAL_SHARED_LIBRARIES += android.hardware.wifi.supplicant-V2-ndk
+LOCAL_SHARED_LIBRARIES += android.system.keystore2-V1-ndk
 LOCAL_SHARED_LIBRARIES += libutils libbase
 LOCAL_SHARED_LIBRARIES += libbinder_ndk
 LOCAL_STATIC_LIBRARIES += libwpa_aidl
@@ -1877,6 +1878,7 @@
 LOCAL_SRC_FILES := \
     aidl/aidl.cpp \
     aidl/aidl_manager.cpp \
+    aidl/certificate_utils.cpp \
     aidl/iface_config_utils.cpp \
     aidl/p2p_iface.cpp \
     aidl/p2p_network.cpp \
@@ -1885,6 +1887,7 @@
     aidl/supplicant.cpp
 LOCAL_SHARED_LIBRARIES := \
     android.hardware.wifi.supplicant-V2-ndk \
+    android.system.keystore2-V1-ndk \
     libbinder_ndk \
     libbase \
     libutils \