Aiidalab-widgets-base

- SmilesWidget: Store SMILES in structure node extras (265 by danielhollas).
- Update the list of disabled OPTIMADE providers. (267 by csadorf)
- Reduce the maximum traceback size for the bug report feature. (266 by csadorf)

* Structure Viewer: add pk to the file name when downloading structure by yakutovicha and csadorf. (246)
* Add header to OptimadeQueryWidget by csadorf. (247)
* Fix issues with code setup by yakutovicha and csadorf. (255)
* Gracefully handling ELN-related issues by yakutovicha and kjappelbaum. (257)
* StructureUploaderWidget: fix reading QE input files by yakutovicha. (259)
*Add cell section to the structure viewer by yakutovicha. (258)

* Fix wrong links, update warning messages. (243)
* Fix computers management logic and links. (244)

* Switch from `computer.name` to `computer.label` and remove the obsolete multi-structure notebook. (236)
* start.py: remove links to the example notebooks. (239)
* Fix the wrong links to the notebooks that were recently placed in the 'notebooks' folder. (238)

* Refactor: rename ligand into the functional group. (224)
* Structure widget: fix supported structure formats link. (225)
* Include jupyter notebooks in docs. (229)
* Revise docs structure. (227)
* Fix: dependency conflicts that caused dependency resolution issues. (232)
* Replace sphinx-rtd-theme with pydata-sphinx-theme. (231)

changes:

- Add OpenAiidaNodeInAppWidget (218).
- Add widgets to interact with ELNs (220).