The current Red Hat config allows to set DefaultCharset to a value.
In certain situations it is necessary to leave it unconfigured thouguh.

Make the content optional, if the value of apache.default_charset is None,
the item is skipped. Otherwise it defaults to UTF-8.

This fixes the following error when Jinja tries to process
`mpm_prefork.conf.jinja` or `00-mpm.conf.jinja`, when it processes the
`max_request_workers` comparison:

```
Unable to manage file: Jinja error: '>=' not supported between instances of 'str' and 'int'
[...]
<IfModule mpm_prefork_module>
  StartServers {{ mpm_param['start_servers'] | d('5') }}
  MaxRequestWorkers {{ mpm_param['max_request_workers'] | d('150') }}
{%- if mpm_param['max_request_workers'] | d('150') >= 256 %}    <======================
  ServerLimit {{ mpm_param['max_request_workers'] | d('150') }}
{%- endif %}
  MinSpareServers {{ mpm_param['min_spare_servers'] | d('5') }}
  MaxSpareServers {{ mpm_param['max_spare_servers'] | d('10') }}
  MaxConnectionsPerChild {{ mpm_param['max_connections_per_child'] | d('0') }}
```

Add filters that convert the values to an int first.

```bash
Examining apache/files/RedHat/modsecurity.conf.jinja of type state
[201] Trailing whitespace
apache/files/RedHat/modsecurity.conf.jinja:26
```

```bash
Examining apache/files/FreeBSD/apache-2.4.config.jinja of type state
[201] Trailing whitespace
apache/files/FreeBSD/apache-2.4.config.jinja:171
```

```bash
Examining apache/files/Debian/apache-2.2.config.jinja of type state
[201] Trailing whitespace
apache/files/Debian/apache-2.2.config.jinja:119
    MaxSpareThreads      75

[201] Trailing whitespace
apache/files/Debian/apache-2.2.config.jinja:136
    MaxSpareThreads      75
```

The source template was missing for RH based systems, only the Debian
file was packaged.

Fix this.

Add server_status state to create a default server_status handler for localhost

Document Stapling options in pillar.example

The formula currently adds a Listen directive for the port '*' if
any configured vhost is configured to listen on :* which does not
work and instead prevents apache from starting.

It is possible to prevent this by setting the
exclude_listen_directive pillar to True but this is a manual
workaround.

Instead, this commit excludes :* Listeners automatically.

The docroot fix from PR#240 worked fine for default servers.
But as soon as one uses vhosts this broke as the vhosts were
created under the docroot in /var/www/html rather than the better
/var/www.

Fix this by differentiating between docroot and wwwdir.
Further allow to override both in Red Hat-style configs.
The override allows to reuse this formula for the softwarecollections
rpms.

* [ssl] [debian] manage ssl.conf with pillars
* [apache] make cyphersuite a list
* [apache/ssl] switch back to strings, lists merge is not good

Including optional per-OS templates

(Solves https://github.com/saltstack-formulas/apache-formula/issues/153)

sysconfig.d/global.conf is re-written by sysconfig on openSUSE

If MaxRequestWorkers is greater than 256 than you also need to set the
ServerLimit value which is defaulted to 256 but has a 20000 hard maximum

* Adding exclude_listen_directive option

* Updating Debian config

* RedHat: Made AddDefaultCharset Directive configurable

* Added description of apache:lookup:default_charset to pillar.example, sane default equals former hardcoded UTF-8

Add gitignore, kitchen-ci files
Add some tests and documentation