Add moving screen projection center calibration to kikuchipy.detectors module

[hakonanes]

Description of the change

• Add kikuchipy.detectors.PCCalibrationMovingScreen class to perform and plot the moving screen projection/pattern center calibration method first presented in this paper
• Expand reference frame user guide notebook with a walk through of how to get a PC estimate using this class
• Other minor improvements to the reference API documentation

Progress of the PR

• Docstrings for all functions
• Unit tests with pytest for all lines
• Clean code style by running black via pre-commit

Minimal example of the bug fix or new feature

>>> import kikuchipy as kp
>>> s_in = kp.data.silicon_ebsd_moving_screen_in()
>>> s_out5mm = kp.data.silicon_ebsd_moving_screen_out5mm()
>>> cal = kp.detectors.PCCalibrationMovingScreen(
...    pattern_in=s_in.data,
...    pattern_out=s_out5mm.data,
...    points_in=[(109, 131), (390, 139), (246, 232)],
...    points_out=[(77, 146), (424, 156), (246, 269)],
...    delta_z=5,
...    px_size=46 / 508,
... )
>>> cal.pc
PCCalibrationMovingScreen: (PCx, PCy, PCz) = (0.5123, 0.8606, 0.4981)
3 points:
[[[109 131]
  [390 139]
  [246 232]]

 [[ 77 146]
  [424 156]
  [246 269]]]
>>> cal.plot()

cal.plot() produces this plot

For reviewers

• The PR title is short, concise, and will make sense 1 year later.
• New functions are imported in corresponding __init__.py.
• New features, API changes, and deprecations are mentioned in the
  unreleased section in doc/changelog.rst.

[hakonanes]

Will merge after checks pass.