fdo#75937 - package galaxy theme in a form we like; cf. fdo#81103.

Change-Id: If920257f141a2dc4208d1fd322b875fdc8315cee
Reviewed-on: https://gerrit.libreoffice.org/10171
Reviewed-by: Muthu Subramanian K <muthusuba@gmail.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>