[fr] app & email
Tidy up installation docs

Demote URL rewriting as the development server should be enough to get
people started and moving along.
Inline rewriting docs.

Fewer longer chapters generally makes the docs easier to scan and less
navigation/heirarchy to wade through.
Rename getting-started and delete fluff.
Start de-duping content in the tutorial.

Having 2 copies of all the installation info makes the docs really
verbose and much harder to maintain. Having fewer duplicate sections
will also help readers as they have less stuff to go through.
[fr] follows #1764 and #1767
correct the description of automodels

Clarify that only table and entity classes are automatic.
[fr] follow #1762
update conventions links in en/fr
small typos in intro
Merge pull request #1768 from cakephp/3.0-fr-new-toc

3.0 [fr] follow new toc #1762
[fr] reorganize all files to follow en version

still english parts to translate
add fixture pluralization
fix sphinx warning
[fr] small typo in intro
Merge pull request #1770 from cakephp/3.0-migr-guide

3.0 update migration guide
Merge pull request #1773 from cakephp/update-installation

Update installation
Fix broken/missing links.
Reduce heading levels.

This removes the tutorials from the TOC which is nice as they are
inlined elsewhere.
Populate the topics page.

It should have some stuff.