Added SN Ia luminosity function calculation

[cmistick]

• Added luminosity function calculation (OM10 - Eq. 18) within supernovae_pop.py
• Added corresponding test function in test_supernovae_pop.py
• Also some minor syntax changes to previous code

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.51%. Comparing base (8a70d74) to head (cf21598).
Report is 91 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #232      +/-   ##
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- Coverage   97.53%   97.51%   -0.02%     
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  Files          58       58              
  Lines        4171     4182      +11     
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+ Hits         4068     4078      +10     
- Misses        103      104       +1     

Files	Coverage Δ
slsim/Sources/Supernovae/supernovae_pop.py	100.00% <100.00%> (ø)

... and 4 files with indirect coverage changes

[nkhadka21]

Hi @cmistick , thank you very much for this PR! the function looks good. You can use this function to sample supernovae magnitudes. For this, you need to compute cdf using luminosity function and sample magnitudes from the cdf. Then, you should get supernovae redshift and magnitudes in your sample. Please look at @emsonmez 's class for the detailed process.