Move gemlite layout to prototype/dtypes

[jainapurva]

This pull request moves GemlitePackedLayout and its implementation from torchao/dtypes/uintx/gemlite_layout.py to torchao/prototype/dtypes/uintx/gemlite_layout.py, and exposed it via torchao.prototype.dtypes while maintaining BC at torchao.prototype.dtypes.uintx with a deprecation warning for future torchao release.
Updates API documentation to reflect the changes

Reference Issue: #2752

[pytorch-bot]

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✅ You can merge normally! (1 Unrelated Failure)

As of commit 5a2bde6 with merge base 842a0c4 ():

BROKEN TRUNK - The following job failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• Run Regression Tests / test-nightly (CPU Nightly, linux.4xlarge, --pre torch --index-url https://download.pytorch.org/wh... / linux-job (gh) (trunk failure)
  test/test_low_bit_optim.py::TestOptim::test_param_groups_optim_name_AdamFp8_device_cpu

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[jerryzh168]

@jainapurva rebase these PRs since CI is fixed now?

[jainapurva]

@jainapurva rebase these PRs since CI is fixed now?

Yes, I'm starting rebase for all