fdo#79676: Initialize with a default chart only from the UI.

When creating an embedded chart object during import, we don't want to
create a default chart which would only mess up the chart data.

With this change, ChartModel::initNew() is a no-op.

Change-Id: Id29659c3885ec1e06bed26d2c851123fb63072cc
fdo#79676: Write unit test for this.

Added a whole bunch of missing component files for handling flat ODF.

Change-Id: Ib9d84be14327a1fd9ff64573ba1f6ba90e0bfc56
fdo#79676: Fix the Java UNO API test with regard to chart tests.

The Java tests rely on the "undocumented" behavior that, when loading an empty
chart document, the chart automaticallly created a "default chart" which is a
column chart with many of its properties filled.  Unfortunately this behavior
caused ugly side effects when loading documents with charts via flat ODF
filter.

I believe fixing the test this way is the right fix.

Change-Id: If3e6c8979da9d0731346ebeedc23c0d3363e83fd