customization: resource types

[ppanero]

Support custom resource types. There are different approaches:

• Add the list as a configuration variable in invenio.cfg.
• Create a command in the CLI (in rdm-records or in the scritps) in order to allow: load, search, removal, and edit of the types.

Note: We must consider the maximum size we expect this list to grow, as in the second case we need to store them in DB. Consider the use of controlled vocabularies.

[ppanero]

Note the comments in #21 about different types, check hierarchical of Galter Lib.