CLI: ansible-doc shows lists of modules & module docs on command-line

## Show listing of all modules

ansible-doc -l

```
...
ohai                  Returns inventory data from _Ohai_
pause                 Pause playbook execution
ping                  Try to connect to host and return `pong` on success.
pip                   Manages Python library dependencies.
postgresql_db         Add or remove PostgreSQL databases from a remote host.
postgresql_user       Adds or removes a users (roles) from a PostgreSQL database.
raw                   Executes a low-down and dirty SSH command
script                Runs a local script on a remote node
seboolean             Toggles SELinux booleans.
selinux               Change policy and state of SELinux
service               Manage services.
setup                 Gathers facts about remote hosts
shell                 Execute commands in nodes.
slurp                 Slurps a file from remote nodes
subversion            Deploys a subversion repository.
supervisorctl         Manage the state of a program or group of programs running via ...
svr4pkg               Manage Solaris SVR4 packages
template              Templates a file out to a remote server.
user                  Manage user accounts
virt                  Manages virtual machines supported by libvirt
wait_for              Waits for a given port to become accessible on a server.
yum                   Manages packages with the _yum_ package manager
```

## Display manual of one module

ansible-doc -m yum

```
> YUM  (/Users/jpm/Auto/pubgit/ansible/ansible/library/yum)

    Will install, upgrade, remove, and list packages with the _yum_
    package manager.

   Options:
   o disablerepo
          _repoid_ of repositories to disable for the install/update
          operation These repos will not persist beyond the
          transaction Multiple repos separated with a ',' New in
          version 0.9.
   o enablerepo
          Repoid of repositories to enable for the install/update
          operation. These repos will not persist beyond the
          transaction multiple repos separated with a ',' New in
          version 0.9.
   o list
          various non-idempotent commands for usage with
          `/usr/bin/ansible` and _not_ playbooks. See examples.
   o name
          package name, or package specifier with version, like
          `name-1.0`.
   o state
          whether to install (`present`, `latest`), or remove
          (`absent`) a package. Choices : present,latest,absent.


    yum name=httpd state=latest
    yum name=httpd state=removed
    yum name=httpd enablerepo=testing state=installed
```

## for insertion into playbook

ansible-doc -s -m yum

```yaml
- name: Manages packages with the _yum_ package manager
  action: yum
        disablerepo=            # _repoid_ of repositories to disable for the ...
        enablerepo=             # Repoid of repositories to enable for the ...
        list=                   # various non-idempotent commands for usage with ...
        name=                   # package name, or package specifier with version, ...
        state=                  # whether to install (`present`, `latest`), or ...
```