Feature/fisheye

[tik0]

This PR adds two new lens types FISHEYE_EQUIDISTANT and FISHEYE_EQUISOLID for the camera as described in blender's fisheye manual. The default camera is still the PERSPECTIVE camera such that the current behavior of syclops is not affected. This PR may still miss some tweaks:

• Output of RGB images is still in RECT folders, which does not make any sense for fisheye images
• frustum feature is currently not supported for fisheye
• intrinsic camera matrix is set to 1 as a quick workaround
• documentation missing

Example
Using the following parameters creates an image as follows

sensor:
  syclops_sensor_camera:
    - name: main_camera_cabin_front
      frame_id: main_camera_link_cabin_front
      lense_type: FISHEYE_EQUISOLID
      resolution: [1920, 1536]
      focal_length: 1.915301618 # mm
      fisheye_fov: 3.4 # rad i.e., 195 deg
      sensor_width: 5.76 # 7.45 mm diagonal (type 1/2.42")
      # ...