examples\controlnet add only_mid_control=true and sd_locked=false

**Is your feature request related to a problem? Please describe.**
The [original controlnet training tutorial](https://github.com/lllyasviel/ControlNet/blob/main/docs/train.md#other-options) mentions the options
* `only_mid_control=True`: _This can be helpful when your computation power is limited and want to speed up the training, or when you want to facilitate the "global" context learning._
* `sd_locked=False`: _This will unlock some layers in SD and you will train them as a whole._

**Describe the solution you'd like**
Please make the option available as well.

**Describe alternatives you've considered**
Going back to the original training script without any optimizations implemented.