[5.6] Use env APP_NAME variable for syslog identifier

[akaroot]

Instead of hardcoded syslog identifier "laravel" I propose to use environment variable APP_NAME.
In case when you have a few Laravel projects on the same machine that log to syslog all of them will write to log with same identifier "laravel" thats not very transparent which message belongs to which project

[jmarcher]

use config('app.name') instead

[akaroot]

you are right, thanks

[browner12]

@akaroot I feel like we should add a fallback of 'laravel'.

$log->useSyslog($this->app->make('config')->get('app.name', 'laravel'), $this->logLevel());

While unlikely that this config key is missing, we don't want an empty value if it is missing.

[akaroot]

@browner12 useSyslog method already has a fallback for empty name
public function useSyslog($name = 'laravel', $level = 'debug', $facility = LOG_USER)

[jmarcher]

@akaroot that value will be overriden if config('app.name') is null, but inside config/app.php there is already a fallback for the app name.

[barryvdh]

Would it make sense to change this to use a hyphen seperated string? When using spaces, it looks kinda weird in Papertrail. Not sure about other services.
Eg. 'My Cool App' would be: my-cool-app, similar to other services (systemd-logind etc)

Papertrail also uses some logic to filter or group by name, which fails when using spaces..

Edit: See #25784