incorporate version 2 of Hydrilla JSON schemas
use pyproject.toml for pytest configuration and move all tests to tests/ directory
include sample source package's REUSE files in sdist
those files are used in automated tests
change translation domain to 'hydrilla-messages'
move locales under builder/
internationalize using Babel
this commit also makes the sdist tarball generated by setuptools REUSE-compliant
facilitate for including other schemas in submodule and expose them to other packages
move to a namespace package under 'hydrilla'
initial commit