Task: Node-type needs revision

[mettta]

This produces "requirement / text / section" (deprecated):

{% set node_type = sdoc_entity.get_type_string() %}
...
node-role="{{ node_type }}"

This produces real node [NAME] as string (new up-to-date):

{% set node_type_string = sdoc_entity.get_node_type_string() %}
...
show-node-type-name="{{ node_type_string }}"

This affects CSS rules in many places, such as:

sdoc-node[node-style="card"][node-role="text"],
sdoc-node[node-style="card"][node-role="section"] { ... }

Need to remove references to old naming, and make the CSS independent of those parameters.