fix(perms): defining the owner is done by “user” sls keyword

See merge request la-crise/discourse-formula!2

fix(config): default posts should be in our defined locale

See merge request la-crise/discourse-formula!1

When building discourse the first time, there are default posts and
categories created.

Setting locale in the “app.yml” configuration permit to have them in
our locale.

feat(setup): install plugins from git URLs

See merge request la-crise/discourse-formula!16

We do not configure them yet.

docs(readme): improve formula documentation

See merge request la-crise/discourse-formula!15

style(setup): use “discourse.setup.caterogies” as model

See merge request la-crise/discourse-formula!14

- make clear the difference in the path between minion and container

- the configuration files should not depends on “service.running”,
  only the execution of the “rake” command.

- the commands should run only if there are changes in their
  configuration files.

feat(setup): create categories

See merge request la-crise/discourse-formula!13

We support only 2 levels of categories for now.

feat(service): do not start the container if it's already runnnig

See merge request la-crise/discourse-formula!12

* discourse/service/running.sls: verify the state of the container
  before running “launcher:start_cmd”.

fix(config): notification mail should be set as soon as possible and configure SMTP authentication mechanism

See merge request la-crise/discourse-formula!11

Some `SMTP` servers require a specific authentication mecanism and
Discourse use `PLAIN` by default.

The notification email must be set as soon as possible for the first
mails created.

feat(themes): install themes during `discourse.setup`

See merge request la-crise/discourse-formula!10

The themes configurations are not yet managed but we provide an
example of what it may look like in `pillar.example`.

fix(settings): applying settings may need retries

See merge request la-crise/discourse-formula!9

And improve documentation.

fix(users): creating users may need several tries

See merge request la-crise/discourse-formula!8

And we must apply settings before creating any user like notification
email for example.

feat(config): support personal TLS certificates

See merge request la-crise/discourse-formula!7

`Discourse` is easy to setup with Let's Encrypt certificates but it's
possible to use other certificates.

* docs/README.rst: document the new ``discourse.tls.enabled`` state.

* discourse/config/tls.sls: create the certificate and the
  corresponding private key from pillars.

* discourse/config/files/default/ssl.crt.jinja: the PEM certificate
  comes from `discourse:tls:cert` pillar and must match the format of
  Nginx `ssl_certificate` directive.

* discourse/config/files/default/ssl.key.jinja: the unencrypted PEM
  key comes from `discourse:tls:key` pillar and must match the format
  of Nginx

* discourse/config/files/default/force-tls.template.yml.jinja: create
  a boot script for the container to force TLS in discourse
  configuration file like `web.letsencrypt.ssl.template.yml` does.

* discourse/config/files/default/app.yml.jinja: adapt the
  configuration depending on the use of Let's Encrypt or personal TLS
  certificates.

* discourse/config/init.sls: configure personal TLS certificates if
  required.

fix(config): lots of SMTP servers do not accept localhost.localdomain

See merge request la-crise/discourse-formula!6

We need to force the `domain` in `app.yml`.

feat(docker): permit to use the vendor repository

See merge request la-crise/discourse-formula!5

You need a new configuration `discourse:docker:repo:use_vendor_repo`
and set it to `true`.

fix(setup): admin users should not receive admin granting email

See merge request la-crise/discourse-formula!4

They are already admin users so don't send a mail each time
`discourse.setup.users` state is run.

feat(oauth2): configure the OAuth2 plugin

See merge request la-crise/discourse-formula!3

Define a `disource:oauth2` dict with settings from
https://github.com/discourse/discourse-oauth2-basic/blob/master/config/settings.yml

IMPORTANT: the settings must not be prefixed with `oauth2_` in the
Salt configuration. This prefix is added by the state.

feat(settings): import discourse settings from Salt configuration

See merge request la-crise/discourse-formula!2

Define a `discourse:settings` dict with settings from
https://github.com/discourse/discourse/blob/master/config/site_settings.yml

Feature/create users

See merge request la-crise/discourse-formula!1

By default, a password reset email is sent to the user.

The default “rake admin:create” ask question, this one takes arguments
from the command line:

- email
- password, can be empty to generate a random one
- enabled, can be True/False to make user active or not
- admin, can be True/False to make user admin or not