Morphology parsers & pipeline blocks

[Helveg]

Describe the work done

• This PR introduces a new set of components based on the new MorphologyParser interface. bsb.morphologies contained a bunch of code to deal with all different ways of parsing morphologies, which is now deferred to these configurable parsers.
• Each MorphologyDependencyNode can now set its own parser, and a new grouping block MorphologyPipelineNode has been added that applies the same pipeline and parsing options to all of the child files to make morphology pipelines easier to reuse.
• [BREAKING] parse_morphology_file/content are now the single point of entry into morphology loading. They summon their own parser based on the args. . All theimport_swc,from_swc`, and other format specific functions ... have been removed.
• mut_excl can deal with short forms.

Still need to update the docs to show how to use these grouped pipelines.

List which issues this resolves:

closes #786 , closes #681

Tasks

• [x] Added tests
• [x] Updated documentation

[codecov[bot]]

Codecov Report

Attention: 101 lines in your changes are missing coverage. Please review.

Comparison is base (d8f4fa3) 73.50% compared to head (9e2885e) 84.03%. Report is 20 commits behind head on main.

Files	Patch %	Lines
bsb/simulation/targetting.py	58.02%	34 Missing :warning:
bsb/storage/_files.py	84.61%	10 Missing :warning:
bsb/core.py	70.00%	6 Missing :warning:
bsb/morphologies/parsers/parser.py	97.19%	5 Missing :warning:
bsb/simulation/adapter.py	84.61%	4 Missing :warning:
bsb/storage/__init__.py	66.66%	4 Missing :warning:
tests/test_configuration.py	96.69%	4 Missing :warning:
bsb/connectivity/strategy.py	82.35%	3 Missing :warning:
bsb/mixins.py	88.46%	3 Missing :warning:
bsb/simulation/results.py	75.00%	3 Missing :warning:
... and 19 more

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #799 +/- ## =========================================== + Coverage 73.50% 84.03% +10.53% =========================================== Files 134 104 -30 Lines 15893 12869 -3024 =========================================== - Hits 11682 10815 -867 + Misses 4211 2054 -2157 ```

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