[AF-842] As an app developer, I want the Migration Helper to help migrate v1 api calls to v2

[svizzari]

:v:

/cc @zendesk/vegemite

Description

This PR adds an -a --auto flag, and attempts more advanced end-to-end transformations of v1 source code, including:

• v1 api sync calls -> async. This is the bulk of the work, including switching from recast to babel.
• injecting ui_widgets js/css conditionally, if used.

When the auto flag is used, the developer is prompted to accept that the results may be unstable before proceeding.

Because this behaviour is behind an auto flag, and requires the developer to opt-in, I'm in favour of releasing as-is, then iterating. Open to suggestions...

This PR goes part-way towards closing #27.

Resolves #27

Tasks

• [x] Update README
• [x] Update documentation
• [x] Update ZAT to support the --auto flag See JIRA Issue

References

• https://zendesk.atlassian.net/browse/AF-842

• 27

Risks

• N/A

[svizzari]

@hoangtrvu 💇 I've renamed the option to -a, --auto as per your comment