Correct migration docs for Bake

Metion that bake is now a plugin, the new template syntax and remove the
theme->template->theme change
Correct typos
[fr] bookmarker tutorial

sauvegardez lui un nouveau mot de passe pour.
devient
sauvegardez lui un nouveau mot de passe.
Merge pull request #2124 from bracketouverte/patch-5

[fr] bookmarker tutorial
Update part-two.rst

Votre méthoder
remplacé par
Votre méthode
Merge pull request #2125 from bracketouverte/patch-6

Update part-two.rst
Merge pull request #2122 from AD7six/3.0-bake-move

Correct migration docs for Bake
Add note about cell template's scope isolation.

Refs cakephp/cakephp#5421
Merge pull request #2126 from cakephp/3.0-cell-isolation

Add note about cell template's scope isolation.
follow and correct #2114, #2122, #2126
[fr] follow 3de8e52 - small typos