[patch] default filename when saving layer

[kolesar]

Use case: create a new data layer, rename it and save as a file. Current JOSM pops up save as dialog with empty filename. Patched version fills default filename with name of the layer if user has renamed that. If layer was not renamed and does not have an associated file (= is called Data layer n) then filename is empty. If layer has associated filename then it is displayed.

Requires patch #12391 that keeps track if layer was renamed by the user. Also requires #12394 that fixes NativeFileChooser.

Refactored telescopic contructors in FileChooserManager to builder pattern to be able to add new settings.

[bastiK]

Replying to kolesar:

Refactored telescopic contructors in FileChooserManager to builder pattern to be able to add new settings.

This is good, but please add javadoc for public methods.

[kolesar]

Added javadoc for public methods.

[bastiK]

In 9670/josm:

applied #12392 - default filename when saving layer (patch by kolesar)

[kolesar]

I have made a mistake in this patch. I have forgot to set allTypes parameter in FileChooserManager when saving OsmDatalayer. Only uncompressed .osm file format was selectable in non-native file chooser.

Attached fix.

[bastiK]

In 9714/josm:

applied #12392 - default filename when saving layer: fix (patch by kolesar)