Add MAGIC sensitivity with references

[vuillaut]

Following the discussions about having a proper reference for MAGIC sensitivity, here is a PR fixing that.

• MAGIC sensitivity (lima 5off as default but others available too) with ref from ctaplot
• plot CRAB spectrum from pyIRF
• cleanup and fix a few formatting issues
• add unit tests on changed functions

The result should look like this:

import matplotlib.pyplot as plt
import astropy.units as u
from lstchain.mc.plot_utils import plot_Crab_SED
from  ctaplot.plots import plot_sensitivity_magic_performance
plot_Crab_SED(10*u.GeV, 100*u.TeV)
plot_Crab_SED(10*u.GeV, 100*u.TeV, percentage=1, linestyle='--', color='gray')
plot_sensitivity_magic_performance()
plt.show()

[maxnoe]

Wat?

ereco = 10**mc_energy ?

[vuillaut]

I did not write that code but good catch.

[vuillaut]

This had nothing to do with this PR but I updated it nonetheless to take the reco energy from the dataframe

[codecov]

Codecov Report

Merging #567 (4513798) into master (9abd542) will increase coverage by 0.53%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master     #567      +/-   ##
==========================================
+ Coverage   50.43%   50.96%   +0.53%     
==========================================
  Files          84       85       +1     
  Lines        7317     7335      +18     
==========================================
+ Hits         3690     3738      +48     
+ Misses       3627     3597      -30     

Impacted Files	Coverage Δ
lstchain/mc/sensitivity.py	98.51% <ø> (-0.01%)	⬇️
lstchain/spectra/crab.py	59.09% <44.44%> (ø)
lstchain/mc/plot_utils.py	46.34% <64.15%> (+30.55%)	⬆️
lstchain/mc/tests/test_plot_utils.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 9abd542...4513798. Read the comment docs.

[moralejo]

This is stalled, but still needed, right? - @vuillaut, can you solve the conflicts?

[vuillaut]

This is stalled, but still needed, right? - @vuillaut, can you solve the conflicts?

Done

[vuillaut]

Merged in #622