Change doc publish workflow to be like c2pa-js

[crandmck]

Although we landed #32, we want the workflows for doc generation in this repo and c2pa-js to be more similar. That repo just runs typedoc in the workflow, using tsconfig.json and typedoc.json instead of CLI options and doesn't use the markdown plugin to generate intermediate .md files.

Currently in this repo, the workflow does rm -rf docs-typedoc to delete the md files that typedoc generates in the docs-typedoc directory. However, the build:docs script in package.json also does this--twice actually (before and after running typedoc). Eli says its better to do it in the workflow than the script. All of this may be unnecessary if we use the c2pa-js approach.