fuse -> ROS 2 : Doc Generation

[methylDragon]

See: #276

Another minor port. This uses rosdoc2 to do the document generation.

Most likely the CI/CD has to be updated to use it!
Also, I tried my best to preserve the settings between rosdoc and rosdoc2, but it's not a one-to-one mapping.

Also, you'll notice that I added \ to some of the package descriptions in package.xml, that's because without them doxygen will truncate the description in the generated docs.

I'll leave it to the maintainers to tweak the doc generation configuration!

Try it out by invoking the following on anything other than fuse_docs (since that uses Sphinx instead of Doxygen):

$ mkdir some_doc_dir_to_not_pollute_the_workspace
$ cd some_doc_dir_to_not_pollute_the_workspace
$ rosdoc2 build --package-path <path_to_rosdoc2.yaml_directory>
$ rosdoc2 open ./docs_output/fuse_constraints/api/html/index.html

Pinging @svwilliams for visibility

[sloretz]

These look good to me locally.

There are a couple issues we can't resolve at the moment.

• The first is fuse_doc requires an upstream fix in rosdoc2 to render correctly: Copy user files into docs_build so they can be referenced in conf.py ros-infrastructure/rosdoc2#47
• The second is rosdoc2 doesn't currently generate anything for interface packages.

However, doc jobs run regularly without needing a new release, so I don't think we should block on those issues. They will get resolved automatically when those two are resolved upstream.

[sloretz]

.hpp now too

[sloretz]

Actually, I ended up removing the rosdoc2.yaml files except for fuse_doc. I found the C++ api docs weren't being generated with the custom configs, but seem to work fine with the default settings.

[methylDragon]

That's very strange.. but not a problem I suppose

[sloretz]

This one is special, and a broken link for now. rosdoc2 doesn't seem to generate any files for interface packages. I left it in so that it will hopefully start working once rosdoc2 supports that.