Update markdown reference to external issues

1. Issue may be not only in jira.
2. Rewrite method for support different external issue trackers
Delete mailer queue because we don't use sidekiq_mailer gem and now the mailer queue doesn't exist any more.
change bash to sh
fix bash-ism
Fix missing links and incorrect display of issue numbers for notes, comments, and merge requests
Moved padding from li to a in dashboard groups / projects listing
Removed redundant spans
Remove duplicated setupNoteForm method
Updated the spring gem and fixed the guard file

Signed-off-by: Jeroen van Baarsen <jeroenvanbaarsen@gmail.com>
don't lookup branch element - it might need to be escaped
Show percentage status on milestone detail page, fixes #485
Update user_management.md

add rails_env to commands
Update markdown.rb

Fix mistake by @qqshfox report
move env to end of lines
fix link_to by @bwrsandman

Add missing '#'
Tar before omnibus build, we all have master access on dev, don't forget to update installation.md
Don't forget to cherry pick into stable.
Use a ? after the $request_uri to perform a valid Redirect while cloning.

fixes #6203

before:

❯ curl -I http://gitlab/namespace/repo.git/info/refs?service=git-upload-pack
HTTP/1.1 301 Moved Permanently
Server: nginx
Date: Sat, 26 Jul 2014 18:20:27 GMT
Content-Type: text/html
Content-Length: 178
Connection: keep-alive
Location: https://gitlab/namespace/repo.git/info/refs?service=git-upload-pack?service=git-upload-pack

after:

❯ curl -I http://gitlab/namespace/repo.git/info/refs\?service=git-upload-pack
HTTP/1.1 301 Moved Permanently
Server: nginx
Date: Sat, 26 Jul 2014 18:23:54 GMT
Content-Type: text/html
Content-Length: 178
Connection: keep-alive
Location: https://gitlab/namespace/repo.git/info/refs?service=git-upload-pack

[ci skip]
add current sign-in date

add current sign-in date to admin section profile view
Enable highlighting for blame

Fixes #3675

Signed-off-by: Jeroen van Baarsen <jeroenvanbaarsen@gmail.com>