Scipion-em

Users:
- add wait protocol. This protocol wait N seconds and then ends.
It is helpful to schedule other protocols using the option "wait for"
- Fix: .em files are handled by xmipp (dimensions now are correct)
- Add symmetry option to export_DB protocol. This will produce the list
of symmetry matrices that PDBe asks for when deposition a new atomic structure
Developers:
- Add method setWrongDefocus to CTFModel (code centralization)
- Add FlexHub model (objects and base methods)

Users:
- Fix: CTFTomoSeries manual subset should work
- Windows' ChimeraX properly called from WSL installations
Developers:
- add attribute isSubParticles to SetOfParticles
- modify __str__ to print SubParticles when appropriate
- remove setOf in SetOfImages.__str__
- EMSet.copyItems and createCopy accepts "itemSelectedCallback" falling back to isEnabled.
- getVersionFromPath improved: works with cuda-11.4.safe (uses regex looking up for numbers)

- Improving performance of the metadataviewer.
- Metadataviewer integration with Chimera and ImageJ - Subsets: Tolerates missing properties in sqlite but present in run.db (CTFTomoseries without TS pointer)

Users:
- Fix: importing non cubic volumes could render 0 elements in dimensions. Now minimum is 1.
Developers:
- ImageHandler.getDimensions uses ImageReader registry and its readers (Xmipp, Tiff, Eman, ...) image
- tiff dimensions (gain, eer, tif, tiff) are swap. They original y were opposite to xmipp and others convention.
- User subset: ready for new metadata viewer using txt files with ids.
- classifyItems method of SetOfClasses updates an existing output set than can be utilized for streaming protocols
- New metadata viewer(BETA). To use it run 'scipion3 pip install metadata-viewer mrcfile'. Right click on outputs should show "Scipion metadata viewer"