Update Install Doc Branch

/cc @marin

What Is A Bug

Fix http clone for public project

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Update Upgrade Document for 6.7

Use the latest version of gitlab-shell which is 1.9.0

Merge branch 'username-keys-content-type' of https://github.com/dmedvinsky/gitlabhq into dmedvinsky-username-keys-content-type
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Conflicts:
	CHANGELOG

Replace gemoji with open source PhantomOpenEmoji

Currently this method responds with `text/html`. It is kind of unusable
if you open it in a browser. The browser thinks it is HTML and renders
it as HTML, meaning new lines are dropped. So it's very hard to
distinguish where the key starts and where it ends.

This commit changes the content type header to `text/plain`.

Cloud Update

/cc @jacobvosmaer @marin @job

Oauth Require Public Email

Does not fix #976 yet, but will reduce the amount of users getting 422 immensly.

Deploy Key Doc

/cc @marin @job @jacobvosmaer

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Changelog O'Reilly

added "Better API for access_levels" sponsorship from O'Reilly to CHANGELOG

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Git Refactoring

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

typo fix

Someone Asked Us To Update The Changelog

Add .adoc file extension for AsciiDoc

Fix registration error info typo

Switched line endings to LF for system_hooks.md