LPS-32192 Move add button from configuration to asset browser in asset publisher

This is before:
![before_cahnges](https://f.cloud.github.com/assets/203395/67613/ab431c42-5f0b-11e2-928d-5949363aae39.png)

And this is after:
![after_cahnges](https://f.cloud.github.com/assets/203395/67615/b2cad996-5f0b-11e2-91dc-f48808e17690.png)