insert menu is sorted by alphabeth rather than logic

[mfrasca]

Expected behaviour

menu items should be in the same order as the plugins define them. so if our garden plugin says accession→plant→location→contact, we should not change it to accession→contact→location→plant.

Actual behaviour

menu items get sorted by label, which also mean that they will potentially follow different orders in different languages.

[mfrasca]

we could also add separators. for example, the garden plug-in knows it follows the taxonomy plug-in, so it can start with a SeparatorMenuItem. and it might want to separate the Contact menu item from the previous ones.

[mfrasca]

[mfrasca]

leaving it as is in 1.0