ggml webgpu: shader library organization (llama/19530)

ggml webgpu: shader library organization (llama/19530)

* Basic JIT compilation for mul_mat, get_rows, and scale (ggml/17)

* scale jit working

* preliminary working jit for getrows and mulmat, needs refining

* simplified mul_mat preprocessing switch statement

* get_rows fixes, mul_mat refinement

* formatted + last edits

* removed some extraneous prints

* fixed get_rows, fixed workgroup dispatch in mul_mat. no gibberish

* small fix

* some changes, working

* get_rows and mul_mat jit fixed and working

* Update formatting

* formatting

* Add header

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Co-authored-by: Neha Abbas <redacted>
Co-authored-by: Reese Levine <redacted>
* Start work on all-encompassing shader library

* refactor argmax, set_rows

* Refactor all but flashattention, mat mul

* flashattention and matrix multiplication moved to new format

* clean up preprocessing

* Formatting

* remove duplicate constants

* Split large shaders into multiple static strings

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Co-authored-by: neha-ha <redacted>