(budget layout) Installation.md: budgets instead of scenarios, new page links
(uninstall, updates) Installation.md: Uninstall… and the update check
(pypi install) Installation.md: pip install from PyPI, no git
(no-code install) Installation.md: start with the Mac app, menu-bar icon and sharing
(desktop app) Installation.md: link the Desktop App page
(wiki docs) Installation.md: documentation page