Add AnyRemoteProvisioner as a more universal AnyConnectionProvisioner

[comps]

The current AnyConnectionProvisioner still needs a Connection type + args + kwargs for initialization, meaning a pre-existing Connection cannot be universally reused. Sure, you can copy over ssh options to a new ManagedSSHConnection, but it won't be the same.

This means a pattern like

with TestingFarmProvisioner(...) as tf:
    tf.provision()
    remote = tf.get_remote()

    with AnyConnectionProvisioner(remote) as p:
        # create multiple "copies" of the 'tf' remote/connection here
        p.provision(10)
        ...

is not currently possible.

This kind of makes sense - for a Provisioner to enforce max_remotes and be able to clean after itself using a Context Manager, the Remote needs to be created by it, so it can call release_hook() via its .release() to remove itself from the Provisioner's list of remotes.

But the original use case of "gimme a system via one Provisioner, then use its .cmd() for X virtual Connections to execute many commands in parallel" is still there.

---

Enter: AnyRemoteProvisioner - you give it a class Remote instance via a function factory and it literally hands those over via a Provisioner style API. No auto-cleanup, no max_remotes, you are responsible for that.

With it, this becomes possible:

with TestingFarmProvisioner(...) as tf:
    tf.provision()
    remote = tf.get_remote()

    # make .release() a no-op, we have only one real connection
    real_release = remote.release
    remote.release = lambda: pass

    try:
        with AnyRemoteProvisioner(lambda: remote) as p:
            p.provision(10)  # no-op
            fake_remote = p.get_remote()  # literally returns the 'remote' object above
            fake_remote.release()  # no-op
            ...

    finally:
        remote.release = real_release  # let TFProvisioner clean up