Add support for multi-nodes on builders

[gabrieldemarmiesse]

Fix #667
Supersedes #668

Here is an example of usage:

$ uv run --with ipython ipython
Python 3.8.20 (default, Oct  2 2024, 16:34:12)
Type 'copyright', 'credits' or 'license' for more information
IPython 8.12.3 -- An enhanced Interactive Python. Type '?' for help.

In [1]: from python_on_whales import docker

In [2]: some_builder = docker.buildx.create()

In [3]: docker.buildx.create("ssh://xxxx", append=True, name=some_builder.name)
Out[3]: python_on_whales.Builder(name='reverent_cray', driver='docker-container')

In [4]: docker.buildx.list()
Out[4]:
[python_on_whales.Builder(name='default', driver='docker'),
 python_on_whales.Builder(name='reverent_cray', driver='docker-container'),
 python_on_whales.Builder(name='quirky_blackburn', driver='docker-container')]

In [5]: docker.buildx.list()[1].nodes
Out[5]:
[BuilderNode(name='reverent_cray0', endpoint='unix:///var/run/docker.sock', flags=['--allow-insecure-entitlement=network.host'], status='inactive', version=None, ids=None, platforms=None, labels=None),
 BuilderNode(name='reverent_cray1', endpoint='ssh://xxxxxxx', flags=['--allow-insecure-entitlement=network.host'], status='inactive', version=None, ids=None, platforms=None, labels=None)]

This requires buildx version >= v0.13.0

@rico132 this should fix all the issues you have with multi-nodes builders :)

Also added more info in the docs about the builders