Refactor model URL constants

[msluszniak]

Description

This PR refactors URLs for models. This also exposed great inconsistencies in naming across hugging face repository:

• Only for llama3_2-3B_qat_lora.pte there is - between name and number of parameters, while for the rest is _.
• For WHISPER_TINY_DECODER en is concatenated in the first part of URL with . and not with - as in the rest of examples.
• There is word all in efficientnet_v2_s_coreml_all and only for that model.
• For some of the models initial name is concatenated with - and the model name as well - phi-4-mini and phi-4-mini_bf16.pte while in others there is - and _ e.g. qwen-2.5 and qwen2_5_3b_8da4w.pte.
• Some model names adds backend info at the beginning: xnnpack_whisper_encoder.pte and some on the end or almost end: style_transfer_udnie_xnnpack.pte.
• ssdlite320-mobilenet-v3-large v3 here is concatenated with - but in model name not: ssdlite320-mobilenetv3-large.pte.
• For craft detector number means size of the intput tensor while for the other suffixed numbers means model sizes.
• Some models B and M meaning billion and million of parameters is capitalized in both first part of url and name: smolLm-2-135M and smolLm2_135M_bf16.pte and for some not: qwen-2.5-1.5B and qwen2_5_0_5b_8da4w.pte.

And there are even more, but you will spot them while correcting rest. I think that there is need to make this unified. And then I will be able to refactor this even more.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update (improves or adds clarity to existing documentation)

Tested on

• iOS
• Android

Testing instructions

No apply

Screenshots

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Related issues

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Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings

Additional notes