Adding edge_tags and vertex_tags to gmshio

[bayswiss]

Describe new/missing feature

gmshio functions model_to_mesh and read_from_mesh return (only) the triplet (mesh, cell_tags, facet_tags), it would be very useful if it returned also edge_tags and vertex_tags, like in the following:

https://github.com/ComputationalPhysiology/cardiac-geometriesx/blob/f7d304600972992299ef6d3938adeebd4c4e2af2/src/cardiac_geometries/utils.py#L47

Suggested user interface

No response

[jhale]

Seems like a good idea - in terms of implementation we should consider using a namedtuple for the tags as the number of return arguments is getting unwieldy.