Document how plugins can get access to a data directory

Commit a252ee599dd5c7ee88dc42ad37065032f06f0de5 introduced the
@PluginData annotation which allows a plugin to get access to a data
directory in which the plugin can story any data it wants. This feature
was only described in the commit message. Add this description to the
plugin documentation.

Change-Id: Ic695f5e6280785a77300b3fc0913189ee8d67254
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
1 file changed