Refactor mqtt service status

[mxmaxime]

Goal

The goal of this PR is to uniform the way we send status to devices and services. For now, we only have the camera so it will be implemented for this service, but the goal is to create something modular for every device/service.

Closes

• closes Improve: mqtt send status #82
• closes refactor: AlarmStatus link to Device #86 we needed it to have access to the device_id data.
• closes feat: add device_id data when publish a picture #74 the device_id is now in the topic.
• closes feat: send bytes over mqtt #92 status is a boolean, so we've fixed this issue.
• fix fix: opencv camera capture in RGB instead of BRG #93 one line of code

WIP

• For a Topic, we enforce to have only one "type" of payload: JSON, Boolean..

[mxmaxime]

Good to go.

[mxmaxime]

We have changed the way status are working so we need to tell the system if nobody is here when the camera is starting up. So basically, if in the first frame we don't detect anybody, we have to publish a message to inform the system.