Fast-oad

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- Changes:
- Added new submodel feature to enable a more modular approach. (379)
- Implemented the submodel feature in the aerodynamic module. (388)
- Implemented the submodel feature in the geometry module. (387)
- Implemented the submodel feature in the weight module. (385)
- Added the possibility to list custom modules. (369)
- Updated high lift aerodynamics and rubber engine models. (352)
- Added custom modules tutorial notebook. (317)
- Bug fixes:
- Fixed incompatible versions of jupyter-client. (390)
- Fixed the naming and description of the virtual taper ratio used in the wing geometry. (383)
- Fixed some wrong file links and typos in CeRAS notebook. (380)
- Fixed issues with variable descriptions in xml file. (364)

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- Changes:
- Now using the new WhatsOpt feature that allows to generate XDSM files without being registered on server. (361)
- Optimization viewer does no allow anymore to modify output values. (372)
- Bug fixes:
- Compatibility with OpenMDAO 3.10 (which becomes the minimal required version). (375)
- Variable descriptions can now be read from comment of XML data files, which fixes the missing descriptions in variable viewer. (359)
- Performance model: the computed taxi-in distance was irrelevant. (368)

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- Changes:
- Enum classes in FAST-OAD models are now extensible by using `aenum` instead of `enum`. (345)
- Bug fixes:
- Incompatibility with `ruamel.yaml` 0.17.5 and above has been fixed. (344)
- Computation of partial derivatives for OpenMDAO was incorrectly declared in some components.
MDA, or MDO with COBYLA solver, were not affected. (347)
- Errors in custom modules are no more hidden. (348)

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- Changes:
- Configuration files can now contain unknown sections (at root level) to allow these files to be used by other tools. (333)
- Bug fixes:
- Importing, in a `__init__.py`, some classes that were registered as FAST-OAD modules could make that the register process fails. (331)
- When generating an input file using a data source, the whole data source was copied instead of just keeping the needed variables. (332)
- Instead of overwriting an existing input files, variables of previous file were kept. (330)
- A variable that was connected to an output could be incorrectly labelled as input when listing problem variables. (341)
- Fixed broken links in Sphinx documentation, including docstrings. (315)

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- FAST-OAD now requires a lower version of `ruamel.yaml`. It should prevent Anaconda to try and fail to update its
"clone" of `ruamel.yaml`. (308)

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- Bug fixes:
- In a jupyter notebook, each use of a filter in variable viewer caused the display of a new variable viewer. (301)
- Wrong warning message was displayed when an incorrect path was provided for `module_folders` in the configuration file. (303)