Reader for NORDIF calibration EBSD patterns

[hakonanes]

Signed-off-by: Håkon Wiik Ånes hwaanes@gmail.com

Description of the change

• Address Reader for NORDIF calibration patterns #224 with a simple reader of NORDIF calibration patterns, read from a Setting.txt file.

Close #224.

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 = kp.load("Setting.txt")
>>> s
<EBSD, title: Calibration patterns, dimensions: (5|480, 480)>

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.