`supported_cubas` optional initialization argument for Mesh/Lattice/Particles

[nathanfranklin]

This issue covers the optional initialization argument for Mesh/Lattice/Particles from @itziakos : https://publicwiki-01.fraunhofer.de/SimPhoNy-Project/index.php/Supported_CUBA_keys_for_container . (Note that the other points from this proposal are covered in #217)

• The Mesh, Particles and Lattice objects should accept at initialization an optional argument passing a set of cuba values that will be supported. Default values for the supported cuba keys for each container type should be decided by the related workgroups and the SSB.

mesh1 = Mesh(name='test1', supported_cubas={CUDSItem.POINT:set(CUBA.VELOCITY), CUDSItem.CELL:set(CUBA.COLOR)})

Description of what needs to be done is being disussed also on the wiki.

[stefanoborini]

No longer relevant. We don't constrain anymore.