Possiblity to autoinstall in Docker Compose (#3353)

* Possiblity to autoinstall in Docker Compose

#fix https://github.com/FreshRSS/FreshRSS/issues/3349

It is simply calling our existing CLI: do-install.php and
create-user.php
https://github.com/FreshRSS/FreshRSS/tree/master/cli

FreshRSS will typically be ready a few seconds before the database, so
introduce a tolerance when the database is not available / up (yet) by
trying a few times to connect. Also useful to avoid service interruption
when DB service is restarted.

Example:

```yml
freshrss-app:
    image: freshrss/freshrss
    container_name:
freshrss-app
    hostname: freshrss-app
    restart: unless-stopped

ports:
      - "8080:80"
    depends_on:
      - freshrss-db

volumes:
      - data:/var/www/FreshRSS/data
      -
extensions:/var/www/FreshRSS/extensions
    environment:
      CRON_MIN:
'*/20'
      FRESHRSS_ENV: development
      FRESHRSS_INSTALL: |-

--api_enabled
        --base_url https://rss.example.net

--db-base freshrss
        --db-host freshrss-db
        --db-password
freshrss
        --db-type pgsql
        --db-user freshrss

--default_user admin
        --language en
      FRESHRSS_USER: |-

--api_password freshrss
        --email user@example.net

--language en
        --password freshrss
        --user admin
      TZ:
Europe/Paris
```

* Minor type f in find

* shellcheck

1 files changed, 2 insertions, 2 deletions

diff --git a/cli/create-user.php b/cli/create-user.php
index dd0c23175..f94a0aa7a 100755
--- a/cli/create-user.php
+++ b/cli/create-user.php
@@ -11,7 +11,7 @@ if (!FreshRSS_user_Controller::checkUsername($username)) {
 
 $usernames = listUsers();
 if (preg_grep("/^$username$/i", $usernames)) {
-	fail('FreshRSS error: username already taken “' . $username . '”');
+	fail('FreshRSS warning: username already exists “' . $username . '”', EXIT_CODE_ALREADY_EXISTS);
 }
 
 echo 'FreshRSS creating user “', $username, "”…\n";
@@ -38,7 +38,7 @@ if (!empty($options['api_password'])) {
 
 invalidateHttpCache(FreshRSS_Context::$system_conf->default_user);
 
-echo '• Remember to refresh the feeds of the user: ', $username , "\n",
+echo 'ℹ️ Remember to refresh the feeds of the user: ', $username ,
 	"\t", './cli/actualize-user.php --user ', $username, "\n";
 
 accessRights();