ENH: tractogram add dps

[AntoineTheb]

Quick description

New script to add data per streamline to a tractogram. Can be colors, streamline ids, sift2 weights, bundle names; your imagination is the only limit.

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Type of change

Check the relevant options.

• 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)
• This change requires a documentation update

Data

https://drive.google.com/file/d/1lagozFxH6k4U8TvaX49e6_sPWj3CptyG/view?usp=sharing

Checklist

• My code follows the style guidelines of this project (run autopep8)
• I added relevant citations to scripts, modules and functions docstrings and descriptions
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I moved all functions from the script file (except the argparser and main) to scilpy modules
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.38%. Comparing base (920ec63) to head (f3bbe90).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1006      +/-   ##
==========================================
+ Coverage   68.34%   68.38%   +0.03%     
==========================================
  Files         420      421       +1     
  Lines       21441    21471      +30     
  Branches     3215     3217       +2     
==========================================
+ Hits        14654    14682      +28     
- Misses       5527     5528       +1     
- Partials     1260     1261       +1     

Components	Coverage Δ
Scripts	69.35% <100.00%> (+0.05%)	⬆️
Library	66.96% <ø> (ø)