docs(wiki): add the initial ncmake wiki - migrate the developer documentation from README and doc/ into wiki pages - developer guides: Getting started, How ncmake understands your app, Building and packaging, Releasing, Per-app tuning, Target reference - CI guides: Workflows, Workflow updater, GitHub App, GitHub PAT, Deleting merged branches - App Store and Installation guides - new pages: Why ncmake (krankerl comparison, DRY) and Step by step - add the Sidebar navigation and replace the placeholder Home.org with Home.md Signed-off-by: ernolf <raphael.gradenwitz@googlemail.com>