This replaces all of the Apache blurbs at the start of each file with an
`# SPDX-License-Identifier: Apache-2.0` string. It also fixes existing
uses to be consistent in capitalization, and to be placed above any
copyright notices.
This removes nearly 3000 lines of boilerplate from the project (only
python files), which no developer cares to look at.
SPDX is in common use, particularly in the Linux kernel, and is the
recommended format for Meson's own `project(license: )` field
Both of these are artifacts of the time before Dependency Factories,
when a dependency that could be discovered multiple ways did ugly stuff
like finding a specific dependency, then replacing it's own attributes
with that dependency's attributes. We don't have cases of that left in
the tree, so let's get rid of this code too
This allow mypy to catch cases where we accidently assign the dependency
name to the type_name, as it sees them as having different types (though
at runtime they're all strings).