Add option to be able to not add IRF to DL3 files

[morcuended]

In case we want to add IRF to DL3 later on. See discussion in #81.

[codecov]

Codecov Report

Merging #94 (939fe36) into main (1599444) will increase coverage by 0.18%.
The diff coverage is 94.28%.

@@            Coverage Diff             @@
##             main      #94      +/-   ##
==========================================
+ Coverage   81.92%   82.11%   +0.18%     
==========================================
  Files          43       45       +2     
  Lines        4443     4579     +136     
==========================================
+ Hits         3640     3760     +120     
- Misses        803      819      +16     

Impacted Files	Coverage Δ
osa/workflow/dl3.py	87.20% <91.66%> (ø)
osa/workflow/tests/test_dl3.py	100.00% <100.00%> (ø)

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[morcuended]

It turned out that the IRF-less DL3 files scheme is not viable (#81). Closing this