Manipulating Linux /etc/group group members (Ref: Issue# 11102)

(1) modules/groupadd.py : Extending by adding three new functions.
adduser, deluser, members . For now it assumes an OS command ‘gpasswd’
is available
.

(2) states/group.py : states.group.present state function is refactored
(along the lines of states.users.present)  to support the following new
options.
  - addusers
  - delusers
  - members

This patch is for review now. This  is currently tested on CentOS(RHEL)
distributions.
Old group.present() state function is renamed as present_old() for now.
Another DeprecationWarning.
Merge branch 'develop' of github.com:saltstack/salt into fix_depwarnings
Add salt-git-ssh script to pass the ssh identity to the git command.
Use salt-git-ssh script as the GIT_SSH command for git when using
private keys on ssh based repositories.
Removed unused import tempfile.
Moved git wrapper script to the package templates directory
Fixed templates package reference in git module
fixed typo
salt.modules.seed: fix bug in _check_install
salt.modules.lxc & salt.runners.lxc: improve cloning support
salt.runners.lxc: remove unused, commented code
salt.modules.seed: remove debug code
#11162 Fix user.present. When a user already exists and their home directory changes we need to move their own directory to the new directory
Merge remote-tracking branch 'upstream/develop' into develop
Make sure the home directory is not change during test run
fix bug in lxc runner
Merge branch 'develop' into lxc
Merge branch 'develop' of github.com:saltstack/salt into fix_depwarnings
mac_user integration tests