* sam : image + prompt encoder, store embeddings

* sam : add the dense img pe in SAM state (#401)

* Add SAM decoder & output masks as png (#418)

* Add loading of decoder layers in Model

* Multiply by hypernet_layer_cnt for ctx_size on model load

* Add decoder layers to py conversion script

* Fix wrong and reversed tensor sizes for decoder

* Add decoder transformer implementation

* Add decoder hypernet and iou prediction mlps

* Add transpose convolution operation and unit test

* Finish mask decoder and write the decoder output in the model state

* Output masks to png after removing padding and upsampling to original size

- Also filter based on the iou treshold
- Additionally filtering based on the stability score and crop boxes
should be done

* Add stb image write in order to output masks from SAM

* Add transpose convolution 2d name and symbol to ggml ops static arrays

* Comment out debug print in transpose convolution test to fix compilation

ggml-ci

* Multithread GGML_OP_ADD_REL_POS operation

* ggml : fix GGML_OP_NAME array

* Disable and comment out debug prints in SAM example

* Add README for the SAM example

* Calculate & filter based on stability score and calculate bounding box

ggml-ci

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Co-authored-by: Yavor Ivanov <yivanov@viewray.com>