Add init files to ml folder

[sivonxay]

No description provided.

[codecov]

Codecov Report

Merging #48 (45e211a) into main (5b0f5e6) will decrease coverage by 21.11%.
Report is 3 commits behind head on main.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##             main      #48       +/-   ##
===========================================
- Coverage   85.16%   64.06%   -21.11%     
===========================================
  Files          43       60       +17     
  Lines        3498     4655     +1157     
===========================================
+ Hits         2979     2982        +3     
- Misses        519     1673     +1154     

Files	Coverage Δ
src/NanoParticleTools/machine_learning/__init__.py	100.00% <100.00%> (ø)

... and 16 files with indirect coverage changes