Simple fit Optimization.jl

[theHenks]

• Use Optimization.jl with LBFGS for all single gaussian fits
• Added tests for single fits

[codecov]

Codecov Report

Attention: Patch coverage is 80.76923% with 5 lines in your changes missing coverage. Please review.

Project coverage is 22.14%. Comparing base (e302032) to head (41b2b89).
Report is 9 commits behind head on dev.

Files with missing lines	Patch %	Lines
src/singlefit.jl	80.76%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              dev      #79      +/-   ##
==========================================
+ Coverage   14.85%   22.14%   +7.28%     
==========================================
  Files          32       33       +1     
  Lines        2841     2940      +99     
==========================================
+ Hits          422      651     +229     
+ Misses       2419     2289     -130     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.