Add new dump format map in aconfig

The `aconfig dump --format map` lists aconfig keys mapped to its boolean
values that represents whether the flag is enabled or not, as seen below:
```
flag.name1=true
flag.name2=false
```

Test: aconfig dump --format map --cache out/soong/.intermediates/build/make/tools/aconfig/aconfig.test.flags/intermediate.pb && inspect output
Bug: 306024510
Change-Id: Ic4990c168f6fa9c87869113ba695c07394adbc67

tools/aconfig/src/commands.rs

@@ -268,6 +268,7 @@ pub enum DumpFormat {
     Verbose,
     Protobuf,
     Textproto,
+    Bool,
 }
 
 pub fn dump_parsed_flags(
@@ -318,6 +319,17 @@ pub fn dump_parsed_flags(
             let s = protobuf::text_format::print_to_string_pretty(&parsed_flags);
             output.extend_from_slice(s.as_bytes());
         }
+        DumpFormat::Bool => {
+            for parsed_flag in parsed_flags.parsed_flag.into_iter() {
+                let line = format!(
+                    "{}.{}={:?}\n",
+                    parsed_flag.package(),
+                    parsed_flag.name(),
+                    parsed_flag.state() == ProtoFlagState::ENABLED
+                );
+                output.extend_from_slice(line.as_bytes());
+            }
+        }
     }
     Ok(output)
 }