Support sdf tag for camera_info topic

[deepanshubansal01]

Desired behavior

The number of /camera_info topic should match the camera image topics. For instance if two camera sensors are being used we would expect two topics for /camera_info eg: /camera1/camera_info and /camera2/camera_info. However in the current design only one /camera_info topic is being created.

Implementation suggestion

Expose an additional optional camera info topic tag alongside image topic tag. If both topic and info tags are provided make sure they are on the same hierarchy level and if not show a warning.

Additional context

The ign-sensors in CameraSensor require image and /camera _info topic to be on the same level of hierarchy for instance: /camera1/image and /camera1/camera_info. If multiple camera sensors with topic names containing single hierarchy (eg: /camera1 and /camera2) is used, this leads to a creation of single /camera_info topic as opposed to two /camera_info topic that should have been created separately for the two cameras. The current behaviour is also inconsistent with gazebo classic.

For changing the topic names refer:

gz-sensors/src/CameraSensor.cc

Lines 566 to 581 in 329e30f

	bool CameraSensor::AdvertiseInfo()
	{
	// TODO(anyone) Make info topic configurable from SDF
	// Info topic must be at same level as image topic
	auto parts = common::Split(this->Topic(), '/');
	parts.pop_back();
	for (const auto &part : parts)
	{
	if (!part.empty())
	this->dataPtr->infoTopic += "/" + part;
	}
	this->dataPtr->infoTopic += "/camera_info";
	return this->AdvertiseInfo(this->dataPtr->infoTopic);
	}

[azeey]

Fixed by #285