Python-on-whales

* Added some methods for Stacks
* Better docs: A diagram was added.
* Fixed a parsing bug on tasks and services.

* Fixed a bug preventing the parsing of services.

Added multiple commands:
* `docker.compose.ps()`
* `docker.swarm.unlock()`
* `docker.swarm.unlock_key()`

* Added `docker.buildx.list()`
* Added `docker.node.ps()`
* Added `docker.stack.ps()`
* Added `docker.compose.push()`
* Added `docker.compose.pull()`
* Fixed a bug that occured when parsing the volume json
* Fixed a bug which prevented the automatic removal of anonymous volumes when using the container context manager.

* added some `docker.plugin` commands: inspect, list, remove...
* Improved the front page of the docs.
* Fixed a bug where python-on-whales could not create a Container object when a gpu was used.
* Added an error message with instructions in case there is a problem when parsing the json response from the daemon.

* Added some `docker.context` commands
* Added `docker.stats`
* Added quite some functions for swarm: `docker.task.list()` `docker.task.inspect()` `docker.service.ps`, `docker.swarm.ca()`, and added Tasks: `python_on_whales.Task`.
* Added more methods for docker services: scale, update, remove, exists.
* Three function of docker compose are now usable (quite experimental still) `docker.compose.up()`, `docker.compose.build()`, `docker.compose.down()`.
* Various documentation improvements.