[bugfix] respect to use multiple `meshes` even if `geometry` tag is defined.

Usually, either a geometry object or file, or, multiple mesh files where set in order to define geometric entities in the main mesh. When parsing a PRJ file, a distinction is made, respectively. Now, there are some benchmarks that include tags for the geometry file and mulitple meshes. This needs to be respected.

If there is a geometry tag, it should be read in. Multiple meshes, even if defined at the same time should, be read in as well.