ENH: add Moran.plot_simulation and Moran_BV.plot_simulation

[martinfleis]

Another port from splot, this time plot_simulation. Dropping aspect_equal keyword as it does not make sense here given the two axes are using distinct units.

I have also added labels to vertical lines indicating I and EI, so that they show up in legend if you do plt.legend().

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.5%. Comparing base (e38e151) to head (9c9dd75).

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #357     +/-   ##
=======================================
- Coverage   81.6%   81.5%   -0.0%     
=======================================
  Files         24      24             
  Lines       3372    3391     +19     
=======================================
+ Hits        2750    2765     +15     
- Misses       622     626      +4     

Files with missing lines	Coverage Δ
esda/moran.py	83.3% <100.0%> (+0.6%)	⬆️

... and 1 file with indirect coverage changes