Instead of generating .html page for each file in an example
project, generate links to code.qt.io, under the correct
path and branch, where the user can browse the example source.
Store all URLs under QT_INSTALL_DOCS/config where other qt5
submodules can access them. The repository name appears in
the URL, so we cannot define a single URL for all modules.
Task-number: QTBUG-74391
Change-Id: I63d4d6d2c352877797b1ee8e057d48c0cd789bff
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
