MAINT-4812 Restore sending snapshot as email from the viewer.

indra/newview/CMakeLists.txt

indra/newview/llfloatersnapshot.cpp

indra/newview/llfloatersnapshot.h

indra/newview/llpanelsnapshotoptions.cpp

indra/newview/llpanelsnapshotpostcard.cpp

indra/newview/llsnapshotlivepreview.cpp

indra/newview/llsnapshotlivepreview.h

indra/newview/llviewermessage.cpp

.../newview/skins/default/xui/de/panel_snapshot_postcard.xml

indra/newview/skins/default/xui/en/floater_snapshot.xml

...a/newview/skins/default/xui/en/panel_snapshot_options.xml

.../newview/skins/default/xui/en/panel_snapshot_postcard.xml

.../newview/skins/default/xui/es/panel_snapshot_postcard.xml

.../newview/skins/default/xui/fr/panel_snapshot_postcard.xml

.../newview/skins/default/xui/it/panel_snapshot_postcard.xml

.../newview/skins/default/xui/ja/panel_snapshot_postcard.xml

.../newview/skins/default/xui/pt/panel_snapshot_postcard.xml

.../newview/skins/default/xui/ru/panel_snapshot_postcard.xml

.../newview/skins/default/xui/tr/panel_snapshot_postcard.xml

.../newview/skins/default/xui/zh/panel_snapshot_postcard.xml