Removed all @Input and @Output annotations

They could lead to unwanted UP-TO-DATE states:

First run will be executed as expected:
```
$ gradle bootstrapReleasePlayResources
:bootstrapReleasePlayResources

BUILD SUCCESSFUL

Total time: 22.356 secs
```

The second run simply states `UP-TO-DATE` and returns without doing anything:
```
$ gradle bootstrapReleasePlayResources
:bootstrapReleasePlayResources UP-TO-DATE

BUILD SUCCESSFUL

Total time: 14.683 secs
```

/cc @bhurling