feat(Mf6Splitter): preserve MFSimulation version & exe_name

[wpbonelli]

• pass original simulation's version and exe_name to split simulation
• close feature: pass exe_name to new simulation in Mf6Splitter #2031

[codecov]

Codecov Report

Merging #2033 (7d823e0) into develop (c223c97) will increase coverage by 1.7%.
Report is 2 commits behind head on develop.
The diff coverage is 100.0%.

Additional details and impacted files

@@            Coverage Diff            @@
##           develop   #2033     +/-   ##
=========================================
+ Coverage     71.1%   72.9%   +1.7%     
=========================================
  Files          259     259             
  Lines        57665   59047   +1382     
=========================================
+ Hits         41029   43064   +2035     
+ Misses       16636   15983    -653     

Files	Coverage Δ
flopy/mf6/utils/model_splitter.py	69.9% <100.0%> (+<0.1%)	⬆️

... and 103 files with indirect coverage changes