As the title says, the Do 22 icon that is the default icon for German basic naval bomber airframes in the base game should be included in the icon pool for these planes in the mod.

Reason for this:
- Germany has a few basic naval bombers at the 1936 start of the game
=> design has only one engine, and floats. It is also named Do 22
=> but there is only an icon resembling the Ar 196, which is, in my opinion, too modern
=> also, the current preset icon, the He 115 icon, is definitely not fitting, since it has two engines

Suggested changes:
- the Do 22 icon should be back as the default icon of the basic naval bomber design Germany has at the 1936 start of the game or at least an option in the icon pool