CLIP (ViT) (#315)

* probably approximatelly correct CLIPTextEncoder

* implemented CLIPEncoderLayer as built-in nn.TransformerEncoderLayer

* replaced embedding layer with simple matrix

* implemented ViT

* added ViT tests

* fixed tests

* added pooler_output for text

* implemented complete CLIPModel

* implemented init

* implemented convert.py and from_pretrained

* fixed some minor bugs and added the README.md

* removed tokenizer unused comments

* removed unused deps

* updated ACKNOWLEDGEMENTS.md

* Feat: Image Processor for CLIP (#1)

@nkasmanoff:
* clip image processor
* added example usage

* refactored image preprocessing

* deleted unused image_config.py

* removed preprocessing port

* added dependency to mlx-data

* fixed attribution and moved photos to assets

* implemented a simple port of CLIPImageProcessor

* review changes

* PR review changes

* renamed too verbose arg

* updated README.md

* nits in readme / conversion

* simplify some stuff, remove unneeded inits

* remove more init stuff

* more simplify

* make test a unit test

* update main readme

* readme nits

---------

Co-authored-by: Noah Kasmanoff <nkasmanoff@gmail.com>
Co-authored-by: Awni Hannun <awni@apple.com>

ACKNOWLEDGMENTS.md

@@ -10,3 +10,4 @@ MLX Examples was developed with contributions from the following individuals:
 - Juarez Bochi: Added support for T5 models.
 - Sarthak Yadav: Added the `cifar` and `speechcommands` examples.
 - Shunta Saito: Added support for PLaMo models.
+- Gabrijel Boduljak: Implemented `CLIP`.