Aiidalab-widgets-base

changes:
- Automated bug reports (209, 219).
- Curate providers for `OptimadeQueryWidget` (211).
- `StructureManagerWidget`: connect structure_node trait to the viewer (217).
- Add `AiidaNodeViewWidget` class. (213).

- Correctly modify an element in the base structure editor (105).
- Set default cell to uploaded structures without a cell (116).
- Improve stability of smiles renderer (117)

API changes:
* Changing StructureManager API (94)

Bug fixes:
* Fix StructureUploadWidget bug that did not allow to import non-cif structures (106)

Improvementes:
* Improve structure editor (102, 103)

Improvements:
- CodeDropdown: hidden codes and codes on disabled computers. (68)
- ComputerDropdown: small widget modifications. (76)
- StructureManagerWidget: add a possibility to set a structure label. (77)

New features:
- Structure editor. (74)

Improvements:

* `ComputerDropdown`: manage disabled computers. (69)
* `SubmitButtonWidget`: allow not disabling submit button after submission and more (70).

* Improve selection trait in structure viewer. (61)
* Improve structure-related widgets. (62)
* Improve process widgets. (63)