Add the ability to depend on the testing backend and opt into it
when running tests/cases, like we do for the other drivers.
The testing backend dependency is removed in the packaging step, as
we don't publish i-slint-backend-testing.
Updated the version from 1.1 to 1.2
Renamed the header to "Slint Royalty-free Desktop, Mobile, and Web Applications License"
Added definition of "Mobile Application" and grant of right
Moved "Limitations" to 3rd section and "License Conditions - Attributions" to 2nd section
Added flexibility to choose between showing "MadeWithSlint" as a dialog/splash screen or on a public webpage
Moved the para on copyright notices to section under "Limitations"
In the ci and on workstations the steps are the same:
1. Install (without building, which would build release)
2. Build debug
3. Run tests
Previously only on Windows the tests were run in debug, because
the "npm install" step in the nodejs test driver would overwrite a
previously created debug build. On windows they are separate DLLs, and
thus co-exist. With this patch we always build debug.
Several tests rely on the testing backend being in place, as it starts
out with a scale factor of 1. The nodejs crate can't depend on the
unpublished testing backend to achieve that, so instead the selector's
backend is used. If that's Qt, then the scale factor is one. If it's
winit, it might be different. To override that, set
`SLINT_SCALE_FACTOR=1` for the nodejs process.
