Move peo package to a different spot to prepare it for PyPI

THIRD_PARTY_NOTICES.md

@@ -1,8 +1,8 @@
 # Third-party notices
 
-peo's own code (the `bridge/`, `docker/` and `tests/` directories and the
-`Dockerfile`) is licensed under the GNU General Public License v3.0 or later;
-see [LICENSE](LICENSE).
+peo's own code (the `peo/`, `docker/` and `tests/` directories, the
+`Dockerfile` and `pyproject.toml`) is licensed under the GNU General Public
+License v3.0 or later; see [LICENSE](LICENSE).
 
 The container image built from this repository also contains the third-party
 software below. None of it is stored in this repository: it is downloaded when
@@ -27,8 +27,8 @@ the image is built. Inside the image, license texts are collected under
   archive of the exact commit that was built. Its dependencies are pinned by
   the `yarn.lock` inside that archive, and the build steps are in this
   repository's `Dockerfile`.
-- **peo** itself ships as Python source code in `/opt/peo/bridge/`. This
-  repository has the rest.
+- **peo** itself ships as Python source code in the `/opt/peo/venv/`
+  virtual environment. This repository has the rest.
 - **Debian packages:** source is available from
   [sources.debian.org](https://sources.debian.org/) and the Debian archive.