syncronize camera_info with images

[LeroyR]

Description

camera_info needs to have the same timestamp as the images. (e.g. for usage with message_filters.TimeSynchronizer)

• give each image from cameras its own CameraInfo
• add configuration for camera topics

This changes cameras to publish a syncronized camera_info for each image. e.g for rgb image:
/mujoco_server/cameras/camera_name/rgb/camera_info
/mujoco_server/cameras/camera_name/rgb/image_raw

Additional configuration options to change topics:
camera_name/topic: defaults to "/mujoco_server/cameras/camera_name"
camera_name/name_rgb: default to "rbg"
camera_name/name_depth: default to "depth"
camera_name/name_segment: default to "segmented"

Checklist

• Required by CI: Code is auto formatted using clang-format.
• Add a brief explanation of your changes to the changelog.

[DavidPL1]

I think this PR should be extended to allow different resolutions per stream type (probably RGB and SEGMENT should use the same) , justifying the need of individual camera infos. To better replicate real setups.
Following rep-0104 we then can keep the model of only publishing camera info when an image was rendered, but change the rendering condition to a subscription of either the Image or the info topic.
I suppose the information on how to align RGB and Depth needs to be specified, too, in case resolutions differ.

[rhaschke]

camera_info needs to have the same timestamp as the images

Are you sure. Usually, camera_info topics are latched and simply provide a fixed message. Therefore, the timestamp shouldn't be relevant.

[LeroyR]

camera_info needs to have the same timestamp as the images

Are you sure. Usually, camera_info topics are latched and simply provide a fixed message. Therefore, the timestamp shouldn't be relevant.

Atleast our cameras do that. By rep-0104 camera_info is send with every image:

Publish CameraInfo Only When Parameters Change
One FAQ is, "Why send CameraInfo with every Image message? Why not only once?" The main answer is that operational parameters (binning, ROI) may change, perhaps rapidly, from image to image.

[LeroyR]

I changed the offscreen_camera to have a CameraInfo publisher for each of the images.

The topics are now configurable such that:

/mujoco_server/cameras/camera_name/rgb/image_raw
/mujoco_server/cameras/camera_name/rgb/camera_info

is used as default - which should match real camera setups.