CI with python 3.11 and removal of some deprecation warnings

[sibirrer]

this PR updates the CI to python version 3.11, replaces scipy interp2d with a non-deprecated version, and updates all the setup(self) to setup_method(self) for testing

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (8600471) 96.21% compared to head (79617f9) 96.20%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #577      +/-   ##
==========================================
- Coverage   96.21%   96.20%   -0.02%     
==========================================
  Files         261      261              
  Lines       22118    22134      +16     
==========================================
+ Hits        21281    21293      +12     
- Misses        837      841       +4     

Files	Coverage Δ
lenstronomy/Cosmo/cosmo_solver.py	100.00% <100.00%> (ø)
lenstronomy/ImSim/image_linear_solve.py	99.20% <100.00%> (ø)
lenstronomy/ImSim/multiplane_organizer.py	100.00% <ø> (ø)
lenstronomy/LensModel/Profiles/gnfw.py	100.00% <ø> (ø)
lenstronomy/Plots/plot_quasar_images.py	100.00% <100.00%> (ø)
lenstronomy/Util/image_util.py	100.00% <ø> (ø)

... and 14 files with indirect coverage changes

[sibirrer]

@ajshajib can you review this PR such that I can merge it and make sure the build is not failing in newer PRs?
Also, is there a way to have in the setup() removed if inherited a unittest class?

[ajshajib]

According to here, setup_method() should be for setting up for testing a specific method and not for everything in the class, and it should take an argument method. I think, in most cases of test classes in lenstronomy, setup() can be replaced with __init__(). The other option setup_class() is a class method, and it would not then be usable to create instance-level variables as in __init__(), I think.

[ajshajib]

@sibirrer, looks good to me overall. I have changed all the setup_method() to __init__(). Now, one test is failing in an unchanged test module, so I think that needs to be looked at if there is a pre-existing issue.

[sibirrer]

@ajshajib it seems that init() does not work for test, as there are warnings like these appearing: ```
test/test_Sampling/test_Likelihoods/test_kinematic_2D_likelihood.py:13
/home/runner/work/lenstronomy/lenstronomy/test/test_Sampling/test_Likelihoods/test_kinematic_2D_likelihood.py:13: PytestCollectionWarning: cannot collect test class 'TestKinLikelihood' because it has a init constructor (from: test/test_Sampling/test_Likelihoods/test_kinematic_2D_likelihood.py)

[ajshajib]

@sibirrer, ok, thanks for the clarification! I have changed back all the def __init__(self) to def setup_method(self, method). Reading the documentation, this method will be called before calling each test method. The method argument is optional for pytest-v3.0, but I left it there in case it's not optional in the future, and this is the default way provided, it's fine not to use the method variable inside the function.

[ajshajib]

@sibirrer, looks good to me, and I approved the PR! Please proceed with merging.