Add Dockerfile to simplify build process

[ruffsl]

No description provided.

[ruffsl]

I've added a few more commits to demonstrate the issues with the existing CMake.

> docker build \
    --target=exporter \
    --output=build .
[+] Building 6.3s (12/14)                                                                                                                                  docker:default
 => [internal] load build definition from Dockerfile                                                                                                                 0.0s
 => => transferring dockerfile: 2.11kB                                                                                                                               0.0s
 => [internal] load metadata for docker.io/library/ros:jazzy                                                                                                         1.5s
 => [internal] load .dockerignore                                                                                                                                    0.0s
 => => transferring context: 210B                                                                                                                                    0.0s
 => [base 1/2] FROM docker.io/library/ros:jazzy@sha256:ee4862fe098e18eba8fb0e9843d57241e404aea12bcba57ed037827f16d98ba6                                              0.0s
 => [internal] load build context                                                                                                                                    0.0s
 => => transferring context: 1.53kB                                                                                                                                  0.0s
 => CACHED [base 2/2] RUN mv /etc/apt/apt.conf.d/docker-clean /etc/apt/ &&     echo 'Binary::apt::APT::Keep-Downloaded-Packages "true";'       > /etc/apt/apt.conf.  0.0s
 => CACHED [prepper 1/3] WORKDIR /opt/rgl                                                                                                                            0.0s
 => CACHED [prepper 2/3] COPY package.xml src/RGLGazeboPlugin/package.xml                                                                                            0.0s
 => CACHED [prepper 3/3] RUN --mount=type=cache,sharing=locked,target=/var/cache/apt     rosdep install -y         --from-paths src         --ignore-src             0.0s
 => CACHED [builder 1/3] COPY . /tmp/RGLGazeboPlugin                                                                                                                 0.0s
 => CACHED [builder 2/3] RUN --mount=type=cache,target=src/,rw     cp -r /tmp/RGLGazeboPlugin src/RGLGazeboPlugin                                                    0.0s
 => ERROR [builder 3/3] RUN --mount=type=cache,target=src/,ro     . /opt/ros/jazzy/setup.sh &&     colcon build                                                      4.6s
------                                                                                                                                                                    
 > [builder 3/3] RUN --mount=type=cache,target=src/,ro     . /opt/ros/jazzy/setup.sh &&     colcon build:                                                                 
0.882 WARNING: Package name "RGLGazeboPlugin" does not follow the naming conventions. It should start with a lower case letter and only contain lower case letters, digits, underscores, and dashes.                                                                                                                                                
0.918 Starting >>> RGLGazeboPlugin                                                                                                                                        
4.342 --- stderr: RGLGazeboPlugin                                                                                                                                         
4.342 CMake Error at RGLServerPlugin/CMakeLists.txt:47 (file):
4.342   file DOWNLOAD cannot open file for write.
4.342 
4.342 
4.342 ---
4.342 Failed   <<< RGLGazeboPlugin [3.42s, exited with code 1]
4.400 
4.400 Summary: 0 packages finished [3.60s]
4.400   1 package failed: RGLGazeboPlugin
4.400   1 package had stderr output: RGLGazeboPlugin
------
Dockerfile:38
--------------------
  37 |     
  38 | >>> RUN --mount=type=cache,target=src/,ro \
  39 | >>>     . /opt/ros/$ROS_DISTRO/setup.sh && \
  40 | >>>     colcon build
  41 |     
--------------------
ERROR: failed to solve: process "/bin/sh -c . /opt/ros/$ROS_DISTRO/setup.sh &&     colcon build" did not complete successfully: exit code: 1

Note: reverting 3f69342 will not produce the expected built output, but avoids violating the expected CMake/colcon norms.

[msz-rai]

LGTM!
Thank you for your contribution.
Since #42 has been merged, please change the base branch to main. I will merge it then.

[ruffsl]

please change the base branch to main.

Done!