feat: add angular's service export

I need to inject parser create in angular factory.

configuration : 
```
 peg: {
            options: {
                trackLineAndColumn: true,
                optimize: 'speed'
            },
            example: {
                src: 'example-peg.txt',
                dest: 'app/components/peg/exampleParser.js',
                angular: {
                    module: 'pegjs',
                    factory: 'exampleParser'
             }
         }
    }
```