Configure WV HAL APEX to be updatable

- add "supportRebootless" to apex_manifest.json
- add <allowed-vendor-apex> sysconfig
- add "on property:apex.com.google.android.widevine.ready=true" to .rc

Now, we can test `adb install` new version of the APEX and see the
service is restarted from the new version.

Note that this doesn't mean that DRM Framework works fine with the
update.

Bug: 248192031
Test: adb install --force-non-staged \
   -i com.android.vending \
   $OUT/vendor/com.google.android.widevine.apex
Change-Id: I7c41b224f0bb55742c0023c23196bba4a09e555f

libwvdrmengine/apex/apex_manifest.json

@@ -1,4 +1,5 @@
 {
     "name": "com.google.android.widevine",
-    "version": 1
+    "version": 1,
+    "supportsRebootlessUpdate": true
 }