Add the option to give an image set a name

After creating a new image set with the Gallery Manager, the name of the image set is shown with a starting capital (proper casing) in the Bean writer. E.g. my "gogreenimageset" is mentioned as "Gogreenimageset", as if I have given a name/title to it. (Which I can't yet, but would like to! Then I would call it GoGreenImageSet). This is the default name for the Bean, with a capital as is the Java convention.

Add the option to give the image set a display name (for all the available translatable languages). Then you can have "gogreenimageset" as the technical name, and the display name can be stored in the hippo:translation messages. The name of the bean should then match the first translation or the version of the English locale.

[description changed after discussion in the comments below]