Rename store and storage modules to make them less confusing

[spl]

This is an issue where we track ideas for names that we would like to consider changing. We may come back to this in the future to wrap them all up together in one big change.

[spl]

Having modules named store and storage is confusing.

[spl]

Having “named graph” and “label” threw me off a bit. I eventually realized that the label is the name of the named graph. What if we called it a labeled graph? Then, it's immediately clear that the label is for the labeled graph.

Also, I see “database” and “named graph” used somewhat interchangeably in places. Perhaps consistency would be better there.

[spl]

type File in PersistentLayerStore. The type is not necessarily a file.

[matko]

PersistentLayerStore doesn't have to be persistent so the name is actually wrong.

[spl]

This is something I've seen in terminusdb, but I'm putting it here for now. I've seen these variable names, and they all seem to refer to the same thing:

• Name
• Graph_ID
• Graph_Name
• DB_Name
• Db/DB
• Instance_Label/Schema_Label
• Composite
• Repo_Name
• Ref_Name