Deprecate Botkit Studio features

[benbrown]

Botkit Studio is being shutdown as a service. We are going to release the dialog editor and trigger API as an open source project.

The features currently included in the Studio sub-library should be updated to remove Studio-specific features, and make the still relevant functionality more generic.

• Remove any calls to Botkit Studio stats/metrics
• Remove/mark as deprecated the "studio" namespace
• Move and/or rename features pertaining to interpreting script JSON from Studio (this could move into a plugin, or just be renamed)
• Remove studio token step from the command line interface
• Update starter kits to remove studio dependencies
• Publish this as a major version instead of a patch as it will not be backwards compatible.

[benbrown]

See: #1544

This pull request removes the Botkit Studio stats/metrics features.

[benbrown]

DONE: botkit-studio-metrics is marked as deprecated, and a new noop version of the package has been published. https://github.com/howdyai/botkit-studio-metrics

[benbrown]

I removed the Studio stuff out of Botkit-starter-web. Still needing updates:

• botkit-starter-slack
• botkit-starter-teams
• botkit-starter-ciscospark
• botkit-starter-facebook
• botkit-starter-googlehangouts