Install a bundle with duffle

[carolynvs]

• Install hello world
• Parameters
• Credentials
• Store the claim
• Install wordpress

This is using two other PRs #232 and #229.

[vdice]

Naturally, this is still in draft, so just giving it a quick looksee and it all is looking good to me 👍

[carolynvs]

I've rebased to include the other merged pull requests and addressed your feedback. Onwards towards victory, claims and credentials! 💨

[carolynvs]

Ok, claims and credentials are in place and this is ready for review @vdice.

After this is merged, I'll submit a PR to duffle to export the functions that I copied. It was a bit more complicated that just copying because I needed to change the duffle "home" so I want to get this in first, and then work with the duffle maintainers on how to best expose these functions as a library, where duffle is an instance that was created with a specific home given to it, instead of always reading from the environment variable (essentially a global).

[carolynvs]

@vdice I ended up making a change to the command structure. The claim name is now an optional positional argument instead of a flag.

$ ./bin/porter install --help
Install a bundle.

The first argument is the name of the claim to create for the installation. The claim name defaults to the name of the bundle.

Usage:
  porter install [CLAIM] [flags]

Examples:
  porter install
  porter install --insecure
  porter install MyAppInDev --file myapp/bundle.json

I started working on porter uninstall and I wanted it to look like porter uninstall mydb or whatever, and wanted symmetry between the commands.