Update title to describe what page is
Check rights on show email page

Check transaction rights for show email and show an error
message for insufficient rights. Manually create the error
message because the error page displayed by Abort shows the
full header and tabs, which covers the message. Since the show
email page has an uncommon layout, better to display the simple
error in place than heavily modify the Error template to handle
it.

Also update other error conditions to use the in-place error
display rather than Abort.

Resolves issues ticket: 27379
Merge branch '4.2/showemail-updates' into 4.2-trunk