This PR was squashed before being merged into the 4.0 branch (closes#8732).Discussion----------Updated the configuration/* filesThisfixes#8725 and required a ton of changes. Besides, I don't really like the config/* articles at all. I'll try to improve things after Symfony 4 release. Thanks!Commits-------6aabd10 Removed links to specific files (they are not easy to maintain)0684c4a Updated the configuration/* files

* 4.0: (28 commits)  typo  Clarifying that our code is just additions  [#8732] Minor tweaks  minor tweaks  updating link to be version independent  Adding yarn install text  Reduce ambiguity of encore installation  Remove svn & changelog articles  Add instructions to install dependencies before using them  Fixed some typos  Fix upgrading to Flex  Removed links to specific files (they are not easy to maintain)  Correction in the console command folder  Fixed some typos  Updated the configuration/* files  Add example usage of the link script  Change service override docs  removing need for annotation route import change  linking directly and marking articles as orphans  adding other dirs  ...

* origin/master: (38 commits)  typo  Clarifying that our code is just additions  [#8732] Minor tweaks  minor tweaks  updating link to be version independent  Adding yarn install text  Reduce ambiguity of encore installation  Remove svn & changelog articles  Add instructions to install dependencies before using them  Fixed some typos  Fix upgrading to Flex  Removed links to specific files (they are not easy to maintain)  Correction in the console command folder  Fixed some typos  Updated the configuration/* files  Add example usage of the link script  Change service override docs  removing need for annotation route import change  linking directly and marking articles as orphans  adding other dirs  ...