This adds support for two things:
* Installing all plugins that a project requires with a single command:
$ pulumi plugin install
* Listing the plugins that this project requires:
$ pulumi plugin ls --project
$ pulumi plugin ls -p
Prior to this change, we had a flat list of files in the
~/.pulumi/plugins directory. This was simple but unfortunately
too naive, since we in fact have multi-file plugins already.
Dumping them in the same directory increases the risk of a
collision. Instead, let's put them in their own directories.
This means, for example, you'll see things like
~/.pulumi/plugins/
resource-aws-v0.11.0-dev-8-g57a0d62/
README.txt
pulumi-resource-aws
Notice that the binary name stays the same -- e.g., in this
case pulumi-resource-aws -- and does not include the version.
This makes it simple to add it to your $PATH in the usual ways
and have it loaded as a preferred location.
This change renames prune to rm, to match what we use for other
similar commands. Someday perhaps we will add a prune that uses
some smarts to prune old plugins, etc.
Also tidy up some minor things about the command. For example,
we now require --all if you want to truly clear the entire plugin
cache. We also print more detail, like the full list of plugins
to be removed, in the confirmation prompt.
