added a "date" attribute to the docusaurus headers. The idea is that they may be rendered where appropriate so that readers can now how old/recent the text is.

updates of documentation - this commit has some bugs that are mentioned in (new) issues - starting from #16

ensure we can do some testing in accordance with https://gitlab.grnet.gr/essif-lab/framework/-/blob/feture-term-engine-v1/docs/terminology-plugin-instructions.md (but doesn't seem to work here)

updated terminology files to use %% rather than {{ ... }}; also, templates have been moved to their own dir