Ask for permission to upload usage stats

This assumes there is analytics.js module.
For now it prompts even for cca help.

Next stage. Add command to change your answer. Should we? Can instruct to just
deleted the file: ~/.cca/config
Try using real analytics module.
Rename getanalytics to analytics loader.
Add 'cca analytics' to enable/disable usage stats collection

Needs some more polish with phrasing messages displayed to the user.
Made general updates to analytics loading.

The updates are mostly style and wording changes.
Also added a bunch of comments.
Made `analytics` commands a special case.

@kamrik had it this way previously; I understand why now.
The only difference from his implementation is that I don't return in the special case, so the command is still reported (if we have permission).
Added a random UUID as a client id for analytics.