
Move the contents of test-requirements.txt and doc/requirements.txt into pyproject.toml as project.optional-dependencies (a.k.a. "extras"). The requirements.txt format is considered pip-specific and nonstandard. While we're at it, fine-tune these per test environment. Change-Id: I477b9685e5d1159086b7a38c9322e07b7c43e2e9