extract logic for creating DocumentFile for export to align naming

src/main/java/de/dennisguse/opentracks/io/file/ExportFile.java

@@ -0,0 +1,21 @@
+package de.dennisguse.opentracks.io.file;
+
+import androidx.documentfile.provider.DocumentFile;
+
+import de.dennisguse.opentracks.content.data.Track;
+
+public class ExportFile {
+
+    public static DocumentFile getExportDocumentFile(Track.Id trackId, String trackFileFormatExtension, DocumentFile directory, String mimeType) {
+        String fileName = getExportFileNameByTrackId(trackId, trackFileFormatExtension);
+        DocumentFile file = directory.findFile(fileName);
+        if (file == null) {
+            file = directory.createFile(mimeType, fileName);
+        }
+        return file;
+    }
+
+    private static String getExportFileNameByTrackId(Track.Id trackId, String trackFileFormatExtension) {
+        return trackId.getId() + "." + trackFileFormatExtension;
+    }
+}

src/main/java/de/dennisguse/opentracks/io/file/ExportFileName.java

@@ -1,10 +0,0 @@
-package de.dennisguse.opentracks.io.file;
-
-import de.dennisguse.opentracks.content.data.Track;
-
-public class ExportFileName {
-
-    public static String getExportFileNameByTrackId(Track.Id trackId, String trackFileFormatExtension) {
-        return trackId.getId() + "." + trackFileFormatExtension;
-    }
-}