aconfig: add namespace field to flag_declaration and parsed_flag

Add a new field to the proto messages flag_declaration and parsed_flag.

The new field will be used verbatim as a parameter when calling
DeviceConfig.getBoolean to read the value of a READ_WRITE flag. See the
DeviceConfig API for more info.

Note: not to be confused with the old namespace field, which has been
renamed to package.

Bug: 285211724
Test: atest aconfig.test
Change-Id: I2181be7b5e98fc334e5277fb5f7e386f1fe0b550
diff --git a/tools/aconfig/src/commands.rs b/tools/aconfig/src/commands.rs
index d252bc4..8be11cc 100644
--- a/tools/aconfig/src/commands.rs
+++ b/tools/aconfig/src/commands.rs
@@ -191,10 +191,12 @@
         package: "com.example"
         flag {
             name: "a"
+            namespace: "ns"
             description: "Description of a"
         }
         flag {
             name: "b"
+            namespace: "ns"
             description: "Description of b"
         }
         "#;
@@ -216,6 +218,7 @@
         package: "com.other"
         flag {
             name: "c"
+            namespace: "ns"
             description: "Description of c"
         }
         "#;