RID_SVXDLG_IMAP conversion to .ui

Change-Id: I6d0ecb693177436a47d1115cdab6d5ec20254f4f
Reviewed-on: https://gerrit.libreoffice.org/10105
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>