Introduce very initial and basic support for running Web Platform Tests
for Ladybird. This change includes simple bash script that currently
works only on Debian and could run tests with patched runner.
For now script to run WPT is not integrated in CI.
There is also a bunch of metadata required to run WPT. To avoid
introducing thousands of files in the initial commit for now it is
limited to run only css/CSS2/floats tests subdirectory.