document/add tool for converting meshes to hdf5 for mesh navigation

[Cakem1x]

Currently, mesh navigation needs a HDF5 mesh to function.
There is a CLI tool in lvr2 with which one can convert different mesh formats to a .h5 mesh. The conversion only works for simple input formats, e.g. .ply.

The goal of this issue is to have an easy to use converter in the mesh_tools pkg, accessible via ros2 cli tools. It is sufficient if it only supports .ply files, but more would be nice. Though only if it works reliably.

When converting, check

• the existing lvr2 script
• where the mesh_map in mesh_navigation loads maps and precomputes values

and consider

• normals (calculations seem off; use weighted face normals instead)
• colors