svtools: encode Base64 the images of the items of the control "ValueSet"
Unfortunately the "Table Design" panel has a "ValueSet" control with
images constructed with the function "CreateDesignPreview". I have no
other choice to export the images to base64 and send it to client.
Perhaps later we can optimize the function "CreateDesignPreview", to
accept SVG pattern or something related.
Change-Id: I34bc8374ffd2a16fbb8fbc2fcd6a41a96bda57a5
Reviewed-on: https://gerrit.libreoffice.org/83538
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Henry Castro <hcastro@collabora.com>
Reviewed-on: https://gerrit.libreoffice.org/83687
Tested-by: Jenkins