Move scale defining options up from ticks

[kurkle]

Closes: #1692 (see for details)

[benmccann]

The very first issue I ever opened in the Chart.js repo was that I didn't understand the difference between ticks, gridlines, and options. Thanks to @etimberg for the great answer there and sorry I never got around to opening a PR for the docs, but you did get me on the path to submitting many others! :-)

In #1692 the issue submitter is talking about ticks and labels as if they were the same thing and I think we could better differentiate as @etimberg commented (#1692 (comment)) on that thread.

Anyway, I agree that this way is better. I do wonder though if it's worth the migration headache since it will affect so many end users and I'm not sure the benefit is that large in this case. I don't feel strongly either way, so am okay in either case

[etimberg]

Perhaps we could offer a migration tool? Paste your config, get the new config? Could do it all in JS

[kurkle]

How about a migrating wrapper too (could use same code)?

Edit: I was thinking about users trying out v3. It would be simple with a config migrating wrapper instead of needing to actually change the config.

[benmccann]

Not quite sure I understand the concept of migrating wrapper, but do agree that some sort of migration helper would be useful