Replace package.properties with manifest.xml

[smehrbrodt]

For full ant support, we will need a working manifest.xml as it cannot be generated during runtime. Would be nice to have an eclipse editor for that and also a way to convert package.properties to manifest.xml.

See also:

• http://bosdonnat.fr/new-export-wizard-for-ooeclipse.html
• https://wiki.openoffice.org/wiki/Documentation/DevGuide/Extensions/File_Format