add bind-home options to local provider

[Mark Mims]

lxc containers take a '--bind-home' and I think a more general '--bind' option.

Let's expose this as an option when deploying containers using local provider. The use case would be development/testing applications. Something along the lines of `juju deploy --bind-home --config myapp.yaml django myapp`... edit the app in your home directory, then touch the wsgi file and the containers redeploy.

There's a bit of a problem in the ambiguity of "home"... my laptop uses /home/mmm but the containers will use /home/ubuntu... but that can be solved.

I'm assuming it'd be better placed in `juju deploy --bind-home` instead of `juju bootstrap --bind-home` or environments.yaml as a 'bind-home' key... but whatever works.

[Mark Mims (mark-mims)]

perhaps a constraint on the local provider might be a better, provider-specific location for this? dunno

[Mark Mims (mark-mims)]

`juju deploy --constraints "bind_map=/home/mmm:/home/ubuntu" django`?

[Jorge Castro (jorge)]

Thumper we talked about this a bit at the sprint, and we'd like to do this as part of our local development story as it's a powerful workflow.