[REVIEW-3-5][REVIEW-3-4] fdo#45995 & fdo#45992

[Noel Power]

Some cherry picking appreciated

handle imported picture attribute from MSO Dialog ( fdo#45995 ) needed 
for 3.5 ( and possibly 3.4... I need to check that )
core:58255c47b1d540fd2493b4ed132aa7fa82da156e

fix support for embedded images for basic Dialogs ( fdo#45992 ) needed 
for 3.5 ( and definitely 3.5, didn't notice that ImageURL property 
wasn't processed for UserForms in oox import when I removed msocximex )

core:468c588875b4858711b708bbc66e0740263bb1f3

Noel