feat: allow defaults to be configured by package singleton dataclass

[matfax]

• Enhancement: Default attributes of paths can now be set in a global singleton mutapath.PathDefaults.
• Fix: not all attributes were cloned

[codecov]

Codecov Report

Merging #16 into master will increase coverage by 0.16%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #16      +/-   ##
==========================================
+ Coverage   96.22%   96.39%   +0.16%     
==========================================
  Files           6        7       +1     
  Lines         424      444      +20     
==========================================
+ Hits          408      428      +20     
  Misses         16       16

Impacted Files	Coverage Δ
mutapath/decorator.py	98.88% <ø> (ø)	⬆️
mutapath/immutapath.py	95.14% <100%> (+0.17%)	⬆️
mutapath/__init__.py	100% <100%> (ø)	⬆️
mutapath/defaults.py	100% <100%> (ø)
mutapath/mutapath.py	100% <100%> (ø)	⬆️