Add gw-too-file to simsurvey

[mcoughlin]

Adds gw-too-file flag to specify the list of skymaps and their exposure times...

[codecov]

Codecov Report

Merging #66 (a4d25ce) into main (a75ac52) will decrease coverage by 0.86%.
The diff coverage is 1.66%.

@@            Coverage Diff             @@
##             main      #66      +/-   ##
==========================================
- Coverage   32.32%   31.45%   -0.87%     
==========================================
  Files          34       34              
  Lines        1553     1599      +46     
==========================================
+ Hits          502      503       +1     
- Misses       1051     1096      +45     

Impacted Files	Coverage Δ
dorado/scheduling/scripts/simsurvey.py	8.51% <1.66%> (-1.24%)	⬇️

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[mcoughlin]

Unit tests pass, adding the flag to account for the GW selections.