Report CLI and platform versions

[mwvaughn]

As part of assisting with routine debugging, it is helpful to ask users to report the CLI version, and it is possible for older versions Abaco to be deployed on various tenants or even offsite, so having that detail is helpful, too.

Implement this as follows:

• Add an abaco version command
• Report CLI version based on a VERSION file embedded in the repo
• Report Abaco version by querying an Abaco service and extracting the version response
• Return either plaintext or JSON responses

[mwvaughn]

Resolved in 60b94b1

[mwvaughn]

Reopening to test