SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
We'll want to remove the LibGUI dependency from the WebContent process.
This is the first basic step of removing unnecessary LibGUI includes
and swapping out GUI::Painter for Gfx::Painter.
