[Flax] Add Textual Inversion (#880)
* add textual inversion flax
* make style
* make style
* replicate vae and unet params
* make style
* minor
* save after end of training
* style
* Temporary fix
Co-authored-by: Suraj Patil <surajp815@gmail.com>
* Add Flax instruction
Co-authored-by: Suraj Patil <surajp815@gmail.com>
