plugin complement

[christophe-david]

This PR implements an enhanced plugin system and closes #393.

It contains following modifications:

• Documentation has been updated. Preview is here.
• Plugin declaration now uses fastoad.plugins as group name instead of fastoad_model
  • The previous group name fastoad_model is still usable, though not mentioned anymore in RTD documentation. It works the same as before, i.e. it expects to have only FAST-OAD modules in the declared plugin package.
  • When using the new group name, configuration files and notebooks can be part of the plugin, and a certain folder structure is expected in the plugin package (see doc).
• The implemented modifications make that models are loaded only at first instantiation of the new class FastoadLoader. Then the loading is not made anymore at startup, which greatly speeds up commands like fastoad -h or fastoad -v.
• CLI and API have been updated (see doc):
  • modified configuration file generation to allow to choose which plugin to use to generate a configuration file
  • modified notebook creation to possibly limit the generated notebooks to the one from a specified plugin. Also, fastoad.api now contains a create_notebooks() method.
  • added a command to get plugin information.
• Modified and added commands in CLI are now unit-tested. It starts the resolution of #407.
• The test of the plugin mechanism has been made independent of actual declared plugins using fixtures in contest.py. It has been rather painful to achieve that 😅.
• Usage of pkg_resources has been removed to use importlib.metadata as it is now recommended.
• tests/testing_utilities.py has been moved to src/fastoad/_utils/testing.py so that there shouldn't be anymore warning when importing copied models in other projects.

[codecov[bot]]

Codecov Report

Merging #409 (61cab9d) into master (4213a19) will increase coverage by 1.00%. The diff coverage is 89.37%.

@@            Coverage Diff             @@
##           master     #409      +/-   ##
==========================================
+ Coverage   90.89%   91.90%   +1.00%     
==========================================
  Files         201      203       +2     
  Lines        8153     8409     +256     
  Branches      854      915      +61     
==========================================
+ Hits         7411     7728     +317     
+ Misses        586      504      -82     
- Partials      156      177      +21     

Impacted Files	Coverage Δ
src/fastoad/api.py	100.00% <ø> (ø)
src/fastoad/exceptions.py	75.00% <0.00%> (-10.72%)	:arrow_down:
src/fastoad/__init__.py	60.00% <57.14%> (-17.78%)	:arrow_down:
src/fastoad/module_management/_bundle_loader.py	94.26% <70.58%> (-1.87%)	:arrow_down:
src/fastoad/_utils/resource_management/contents.py	76.47% <76.47%> (ø)
src/fastoad/cmd/exceptions.py	84.61% <77.77%> (-15.39%)	:arrow_down:
src/fastoad/module_management/_plugins.py	90.66% <90.41%> (-9.34%)	:arrow_down:
src/fastoad/cmd/api.py	91.00% <92.06%> (+0.25%)	:arrow_up:
src/fastoad/_utils/resource_management/copy.py	96.55% <94.11%> (-3.45%)	:arrow_down:
src/fastoad/_utils/testing.py	83.33% <100.00%> (ø)
... and 8 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 4213a19...61cab9d. Read the comment docs.