void setFileID(String newFileId) {
			if (fileId != null) {
				unmapFileID(fileId);
			}
			fileId = newFileId;
			if (fileId != null) {
				mapFileID(fileId, this);
			}
		}
Set this items parent, name and storage name and add the modified item
to the specified parent's item map.  The FileID will be read from the
existing property file
@param parent
@param name
@param fileId unique file ID from property file content
@param storageName
Ghidra/Framework/FileSystem/src/main/java/ghidra/framework/store/local/IndexedLocalFileSystem.java