Add default (mock) Contexthub HAL 1.1 impl

Current implementation exposes a mock context hub, but with no nanoapps.

Bug: 135951924
Test: compile only (will be covered by VTS in a follow-up)
Change-Id: I7a13527f303ce1bcacac8c6be9f081b0838cdc68
diff --git a/contexthub/1.1/default/android.hardware.contexthub@1.1.xml b/contexthub/1.1/default/android.hardware.contexthub@1.1.xml
new file mode 100644
index 0000000..388f781
--- /dev/null
+++ b/contexthub/1.1/default/android.hardware.contexthub@1.1.xml
@@ -0,0 +1,11 @@
+<manifest version="1.0" type="device">
+    <hal format="hidl">
+        <name>android.hardware.contexthub</name>
+        <transport>hwbinder</transport>
+        <version>1.1</version>
+        <interface>
+            <name>IContexthub</name>
+            <instance>default</instance>
+        </interface>
+    </hal>
+</manifest>