Make Software CaRD validation configurable via hermes.toml

[zyzzyxdonta]

Currently, an empty config is used:

hermes-plugin-software-card/src/hermes_plugin_software_card/curate.py

Line 45 in 7bc1d97

self._shacl_graph = make_shacl_graph(Config.from_dict({"policies": {}}))

This should be loaded from hermes.toml, similarly to the command line tool:

https://github.com/softwarepub/software-card-policies/blob/b44862277d56045c1a9005fbf84805fced9ded68/config.toml