all: Normalize cloud_provider options for bosh-init

[evandbrown]

Restructure the mbus, ntp, and blobstore configuration properties to be
consistent with existing CPIs. Addresses #31.

A bosh-init manifest's cloud_provider.properties section should include the following keys:

• google
• agent
• blobstore
• `ntp

For example:

properties:
      google: *google_properties
      agent: {mbus: "https://mbus:mbus-password@0.0.0.0:6868"}
      blobstore: {provider: local, path: /var/vcap/micro_bosh/data/cache}
      ntp: *ntp

This is a departure from previous versions of the CPI that expectd agent and ntp keys to children of the agent key.

[cfdreddbot]

Hey evandbrown!

Thanks for submitting this pull request! I'm here to inform the recipients of the pull request that you and the commit authors have already signed the CLA.