As prerequisit to implement the switch of subjects to datastreams implement tests for LCSH and RAMEAU identifiers

[wgresshoff]

Is your feature request related to a problem? Please describe.

In the datastreams version of subjects (inveniosoftware/invenio-vocabularies#322) several identifier schemes should be supported, e.g. gnd, lcsh, rameau and more.

Describe the solution you'd like

Implement is_lcsh, is_rmeau, normalize_lcsh, normalize_rameau.

Describe alternatives you've considered

None.

Additional context

The rameau identifier is an ark implementation (e.g. https://data.bnf.fr/ark:/12148/cb16656930x). It might be sufficient to just check if an id is an ark. So it might be a good idea to first fix #79