CLI: Version consistency check

[shilman]

Half the issues I see have inconsistent @storybook/* versions. Recent examples:

• Navigation broken after adding showRoots option #11381 6.0 but addon-notes 5.3.19
• storybook not working (IE11 & chromium) #9242 6.0 but addon-info / addon-options 5.3.19

Users should remove these deprecated 5.3.x packages which are pulling in 5.3 dependencies. Furthermore, users should generally upgrade all @storybook/* to the same version when they upgrade.

We should:

• check for @storybook/* versions on startup
• warn about version inconsistencies
• for deprecated addons (info, notes, options, centered, contexts), provide migration instructions

[shilman]

Hurrah!! I just released https://github.com/storybookjs/storybook/releases/tag/v6.0.0-beta.40 containing PR #11396 that references this issue. Upgrade today to try it out!

You can find this prerelease on the @next NPM tag.

Closing this issue. Please re-open if you think there's still more to do.