Package DTE as a proper installable Python package and expose unified CLI entry point

[igoropaniuk]

It would be great to package DTE as a proper installable Python distribution, so
users can install it with pipx install (or pip install into a venv) and get a
dte (or we call call it qcom-dte following the approach for other qualcomm tools, like qcom-ptool or qcom-capsule-tool) console command instead of cloning the repo and running python3 run.py.

Current install/run flow:

git clone https://github.com/qualcomm/DTE.git
cd DTE
pip install -r requirements.txt
python3 run.py <file>.dtb

Proposed:

pipx install qdte      # or: pip install into a venv
dte <file>.dtb # or: qcom-dte <file>.dtb

Benefits:

• One-command install with isolated dependencies (no manual requirements.txt step).
• A real entry-point command (dte/qdte) on $PATH.
• Proper metadata and version pinning; easier to cut releases (and optionally
  publish to PyPI later). Also we can package it into proper deb package as well
• Standard python -m build / wheel artifacts for CI and distribution.

I'd be happy to put up a PR for initial transition, let me know what do you think

[igoropaniuk]

Yeping-Song please let me know what you think