A handful of UX improvments for config:
- `pulumi config ls` has been removed. Now, `pulumi config` with no
arguments prints the table of configuration values for a stack and
a new command `pulumi config get <key>` prints the value for a
single configuration key (useful for scripting).
- `pulumi config text` and `pulumi config secret` have been merged
into a single command `pulumi config set`. The flag `--secret` can
be used to encrypt the value we store (like `pulumi config secret`
used to do).
- To make it obvious that setting a value with `pulumi config set` is
in plan text, we now echo a message back to the user saying we
added the configuration value in plaintext.
Fixes#552
This PR adds `login` and `logout` commands to the `pulumi` CLI.
Rather than requiring a user name and password like before, we instead require users to login with GitHub credentials on the Pulumi Console website. (You can do this now via https://beta.moolumi.io.) Once there, the account page will show you an "access token" you can use to authenticate against the CLI.
Upon successful login, the user's credentials will be stored in `~/.pulumi/credentials.json`. This credentials file will be automatically read with the credentials added to every call to `PulumiRESTCall`.
