skpkg: add cookiecutter.json, fix rendering issues in readme, add index.rst, add conftest.py, update requirements folder, update manifest.in

[zmx27]

No description provided.

[zmx27]

@sbillinge ready for review. As I was going through the checklist for the release issue, I realized that the docs won't build, among other things. This PR serves to fix the issues I've noticed. The docs now build:

Wow, I keep noticing more issues haha

[zmx27]

CLI utility provided by skpkg. Got this from package update

[zmx27]

Points to the file src/diffpy/distanceprinter/distanceprinter_app.py

[sbillinge]

please paste the results of running pytest locally. Also please check that all the requirements files are present and up to date. T hen I can merge

[zmx27]

Here is the result of running pytest locally:

================================= test session starts =================================
platform darwin -- Python 3.13.9, pytest-8.4.2, pluggy-1.6.0
rootdir: /Users/zhimingxu/BillingeGroup/diffpy.distanceprinter
configfile: pyproject.toml
plugins: env-1.2.0, cov-7.0.0
collected 2 items

tests/test_distanceprinter.py .                                                 [ 50%]
tests/test_version.py .                                                         [100%]

================================== 2 passed in 1.23s ==================================

And yes, with the addition of pip.txt in this PR, all of the requirements files are present and up to date.

[sbillinge]

Let me know when this is ready for release

[sbillinge]

It is in my mind to make this public too. I think it could be widely useful. Please could you look into that? We would need to give it the same treatment we gave srxconfutils