Add fr (French) language fallback for br, nrm, oc

Add fr (French) language fallback for br, nrm, oc

A few languages of France which had not been provided with a
language fallback yet. Data clearly shows that French is known
by nearly all of their speakers and by a large majority of the
users of Wikimedia projects in those languages, while English
is known by a minority. For br and oc, no gender namespaces,
date formats etc. will be inherited.

https://translatewiki.net/wiki/Thread:Portal_talk:Br/Use_French_when_no_translation
https://translatewiki.net/wiki/Thread:Portal_talk:Nrm/Use_French_when_no_translation
https://translatewiki.net/wiki/Thread:Portal_talk:Oc/Use_French_when_no_translation

All translators have been warned and can comment above.

Additionally, there were various discussions on local wikis:
https://oc.wikipedia.org/w/index.php?diff=2040712
https://br.wikipedia.org/w/index.php?curid=130192
https://nrm.wikipedia.org/w/index.php?diff=206241

Incidentally, a majority of editors supports the fallback,
although 1 user for each of br and oc is against, citing
bad feelings/reactions towards France the state.

Change-Id: I02fc9af984f593c9e249b0007aec0ec0b4f95457