Added .gitignore to datastore_server

SVN: 22603

datastore_server/.gitignore

+/targets
+/temp-testng-customsuite.xml
+/test-output
+/.dynamic_property_evaluator_queue
+/.shredder
+/.updater
+/tmp
+/clean-up-tasks

datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/.gitignore

+/CopyOfShareIdManager.java

datastore_server/source/java/ch/systemsx/cisd/openbis/dss/generic/server/plugins/standard/.gitignore

+/CopyOfAbstractDropboxProcessingPlugin.java