Replace the legacy dgeni/gulp documentation pipeline with TypeDoc and typedoc-plugin-markdown. Generates plugin README files with extracted @Plugin() decorator metadata. Register custom JSDoc tags used by plugin source files.
* feat(Cooee): add Cooee plugin * chore(Cooee): update document * Update index.ts * feat(lets-cooee): add event observable * docs(lets-cooee): add lets-cooee documentation Co-authored-by: Daniel Sogl <daniel@sogls.de>