Handle case of size 0 file.
Improve group arguments allowing to specify input type (id or name)

In add, joingroup, leavegroup subcommands, group can be passed by id, by name
or by id_or_name as a positional argument.
Fix inverted id and name in group addition message

Also explicitely state name and id in user addition message
Refactor find_group() method and expose group ID/name ambiguity

find_group() now systematically looks up for group by ID and by name for a
given input. Found groups are resolved in a second step and a warning/error is
raised is multiple groups are found, e.g. for two different group where
id_or_name is the ID of the one and the name of the other.
Do not return group if ambiguous group is found in find_group()
Fix download text.
Add name option to download.
Review download of image sequence to allow to set the name.
Check file with same name already exists.
Review file loading sequence.
Clean code.
Make sure the loader is created only once.
Remove print out.
Review name checker.
Replace internal method by method from FileUtilsName.
Review path check
Do not rename the ome-tiff file silently (see #9469)
Fix extension check.
Remove method setControls
Download option available when the original metadata exists.