[scribus] chain frames, "do not" link them

[ale rimoldi]

p.p.s.: i've checked how it's called in the CSS3 regions proposal, a
context that also has to avoid the confusion with the hypertext links:
they're calling it "flow", with the verb "flow" and both nouns "flow"
and (not as often) "chain".

https://www.w3.org/TR/css-regions-1/

in both the CSS and scribus context we would a confusion with the
flowing around images... with the little advantage, that most of the
time the two word will not be in the same context (at least not in the
menus, since text flow is a text property and the the other flow a
shape (item) one).