feat: Add LHE writing functionality

[APN-Pucky]

I decided to add a tolhe() function to every class (since it is neither xml nor a simple string).
The format strings can maybe still be improved?
read_lhe_init() now returns a LHEInit object combining weights, procinfo and initinfo. For backwards compatibility I added the get/set there so that LHEInit will still behave as previous LHEInit, what is now LHEInitInfo.

The tests can probably still be extended, but for the first draft I just hardcoded them for one file.

Already includes #232 and #231
Closes: #229

Squash Commit summary:

feat: Add LHE writing functionality

* Add `LHEInitInfo` dict class that contains only the first line of the <init> block.
  Previously this was in `LHEInit`. The new `LHEInit` contains more lhe-init variables
  `procInfo`, `weightgroup` and `LHEVersion` needed for writing LHE files. For
  backwards compatibility `LHEInit` maps to `LHEInitInfo` unless `procInfo`,
  `weightgroup` or `LHEVersion` are requested.
* Implemented `tolhe` methods for `LHEEvent`, `LHEEventInfo`, `LHEParticle`, `LHEInit`, 
  `LHEInitInfo`, and `LHEProcInfo` classes to support converting objects to LHE
  formatted strings.
* Added new functionality to write LHE files to both string and file, with options for
  gzip compression and different weight formats.

[codecov]

Codecov Report

Attention: Patch coverage is 90.00000% with 8 lines in your changes missing coverage. Please review.

Project coverage is 91.17%. Comparing base (584c03f) to head (ef0376f).
Report is 2 commits behind head on main.

Files	Patch %	Lines
src/pylhe/__init__.py	90.00%	1 Missing and 7 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #233      +/-   ##
==========================================
- Coverage   91.48%   91.17%   -0.32%     
==========================================
  Files           2        2              
  Lines         235      306      +71     
  Branches       54       78      +24     
==========================================
+ Hits          215      279      +64     
- Misses         16       17       +1     
- Partials        4       10       +6     

Flag	Coverage Δ
unittests-3.10	90.84% <90.00%> (-0.22%)	⬇️
unittests-3.8	90.84% <90.00%> (-0.22%)	⬇️

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[matthewfeickert]

Thanks @APN-Pucky. I'm going to say LGTM as it passes CI.

Maybe @eduardo-rodrigues can give it a look over too?

@APN-Pucky can you please add a summary commit message to the PR body that can be copy-pasted in for the squash and merge?

[APN-Pucky]

@APN-Pucky can you please add a summary commit message to the PR body that can be copy-pasted in for the squash and merge?

Done.

[matthewfeickert]

Done.

Thanks @APN-Pucky! Can you now rebase this off of main now that PR #232 is in (and fixup the merge conflict there)? After that I think this is good to go.

[APN-Pucky]

Thanks @APN-Pucky! Can you now rebase this off of main now that PR #232 is in (and fixup the merge conflict there)? After that I think this is good to go.

✔️

[matthewfeickert]

Thanks @APN-Pucky. I'll leave this open for @eduardo-rodrigues to look at, but if he hasn't reviewed it by Friday 2024-08-22 I'll merge this.

We can then get a minor release out to PyPI as @agbuckley asked about in Discussion #238.

[agbuckley]

Thanks!!

[eduardo-rodrigues]

Hi everyone. As you could guess I had been away and offline.

This is a really nice addition :+1!

My only comment to you @APN-Pucky is that the functionality should be visible as an example notebook for sure, probably in a dedicated new notebook (otherwise many will not realise writing is now available).
Likewise I would add a little paragraph/sentence in the README.