Round floats for hashing in instrument module, use __slots__

[maxnoe]

No __slots__ for CameraGeometry as it is incompatible with using lazyproperty.

[codecov]

Codecov Report

Merging #1986 (5cecb1c) into master (4272a4b) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1986      +/-   ##
==========================================
+ Coverage   92.21%   92.24%   +0.02%     
==========================================
  Files         193      193              
  Lines       15379    15430      +51     
==========================================
+ Hits        14182    14233      +51     
  Misses       1197     1197              

Impacted Files	Coverage Δ
ctapipe/instrument/camera/geometry.py	90.67% <100.00%> (-0.03%)	⬇️
ctapipe/instrument/camera/readout.py	92.75% <100.00%> (+0.10%)	⬆️
ctapipe/instrument/optics.py	90.56% <100.00%> (+0.18%)	⬆️
ctapipe/instrument/telescope.py	86.84% <100.00%> (+0.35%)	⬆️
ctapipe/calib/camera/pedestals.py	95.87% <0.00%> (ø)
ctapipe/io/tests/test_table_loader.py	99.42% <0.00%> (+0.02%)	⬆️
ctapipe/io/tableloader.py	96.52% <0.00%> (+0.59%)	⬆️
ctapipe/core/container.py	89.89% <0.00%> (+1.28%)	⬆️

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[maxnoe]

Sorry, had to fix an issue with the docs build.