Removing installation instructions

We have this multiple other places
minor #751 Removing installation instructions (weaverryan)

This PR was merged into the 2.3 branch.

Discussion
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Removing installation instructions

Hey guys!

We have the installation instructions in too many places. Ultimately, as we get the new symfony.com/download page and the downloader, this will reduce to just *one* spot (likely the download page, with a hand-off to continue by reading the docs).

On this repo, we should have no installation docs - it should just point to the central place. I also think we can just link to the current version of all of the docs for the bundle.

Thanks!

Commits
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22589ce Removing installation instructions
changed version to 2.3 in the README
Merge branch '2.3' into 2.5

* 2.3:
  changed version to 2.3 in the README
  Removing installation instructions

Conflicts:
	README.md
[Tests] Ignored the Resources and Tests directories for the new AppBundle
bug #756 [Tests] Ignored the Resources and Tests directories for the new AppBundle (saro0h)

This PR was merged into the 2.3 branch.

Discussion
----------

[Tests] Ignored the Resources and Tests directories for the new AppBundle

Commits
-------

876ebcd [Tests] Ignored the Resources and Tests directories for the new AppBundle
Merge branch '2.3' into 2.5

* 2.3:
  [Tests] Ignored the Resources and Tests directories for the new AppBundle