French localization of login page (#4996)

* French localization of login_fr.properties

* French localization of simple-header_fr.properties

* French localization: sentenced changes in login_fr.properties

* Update core/src/main/resources/jenkins/model/Jenkins/login_fr.properties
Co-authored-by: NAdrien Lecharpentier <adrien.lecharpentier@gmail.com>

* Update core/src/main/resources/jenkins/model/DefaultSimplePageDecorator/simple-header_fr.properties
Co-authored-by: NA. Jard <angelique.jard@gmail.com>

* Contributor name added
Co-authored-by: NAdrien Lecharpentier <adrien.lecharpentier@gmail.com>
Co-authored-by: NA. Jard <angelique.jard@gmail.com>

core/src/main/resources/jenkins/model/DefaultSimplePageDecorator/simple-header_fr.properties

+# The MIT License
+#
+# Copyright (c) 2020 Solène Garda-Krebs
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+
+Welcome\ to\ Jenkins!=Bienvenue dans Jenkins !

core/src/main/resources/jenkins/model/Jenkins/login_fr.properties

@@ -20,8 +20,9 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 # THE SOFTWARE.
 
-User=Utilisateur
+signIn=S''identifier
+signUp=<a href="signup">Cr\u00e9ez un compte</a> si vous n''\u00eates pas encore membre.
+Invalid\ username\ or\ password=Nom d''utilisateur ou mot de passe incorrect
+Username=Utilisateur
 Password=Mot de passe
-Remember\ me\ on\ this\ computer=Conserver mes informations sur cet ordinateur
-login=S''identifier
-signUp=<a href="signup">Créez un compte</a> si vous n''êtes pas encore membre.
+Keep\ me\ signed\ in=Garder ma session ouverte