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
Moved padding from li to a in dashboard groups / projects listing
Removed redundant spans
Remove duplicated setupNoteForm method
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 '#'
Document the extra.sign_in_text setting for CE
add current sign-in date

add current sign-in date to admin section profile view
Adding Spinach tests for 'search issues by description field' feature
Fixing requested changes for 'search issues by description' tests
Update redcarper gem
add missing config files to check during release process
Fix naming convention of LDAP tests