Update Hypercane to accept NLA collection identifiers as input for discovering mementos

[Shawn M. Jones]

Hypercane currently accepts an input type of archiveit and a number as an input argument that identifies the Archive-It collection. We want to do the same, so someone can type Hypercane commands like:

# hc identify -i nla -a 13000 ...

Once this AIU issue is complete Hypercane will be able to acquire metadata and a list of URI-Ms for each NLA collection. We just want to connect all of this together into a new input type.

We will likely need to add functions for NLA that function like generate_archiveit_urits.

We will also need to update discover_mementos_by_input_type, discover_timemaps_by_input_type, and discover_original_resources_by_input_type to support a new input type of nla.

I think these are the only changes needed, but we will need to test to make sure.