Add lplot! for Dict{Symbol, NamedTuple}

[fhagemann]

Some functions in LegendSpecFits return a dictionary of reports, for example LegendSpecFits.fit_peaks.

This PR adds a plot recipe to create a plot from the individual reports but still provides a title etc.
I also modified the plot recipe for histogram fits with custom components.

result_fit, report_fit = LegendSpecFits.fit_peaks(result_simple.peakhists, result_simple.peakstats, th228_names;
    e_unit=result_simple.unit, calib_type=:th228, m_cal_simple=m_cal_simple)

LegendMakie.lplot(report_fit, figsize = (600, 400*length(report_fit)), 
    title = get_plottitle(filekey, det, "Peak Fits"; additiional_type=string(e_type)))

It is not so easy for this plot to prevent the legend to clash with the histogram or fit lines.
One could adjust the plot recipe of the histogram fit such that the background line is always plotted in the lowest 20%. However, this only works, if there is a "flat" background component.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.71%. Comparing base (0e23b46) to head (bd4a308).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main       #9      +/-   ##
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+ Coverage   91.11%   91.71%   +0.60%     
==========================================
  Files           9        9              
  Lines         304      314      +10     
==========================================
+ Hits          277      288      +11     
+ Misses         27       26       -1     

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