first run: skip account creation if they already have accounts

[derhuerst]

This PR addresses #3583 by adding a simple "skip" button to the first run modal, if the user has one or more accounts.

[coveralls]

Changes Unknown when pulling b980e7a on jr-first-run into ** on master**.

[gavofyork]

they should click through the license whatever; skip button should only be there after that.

[derhuerst]

@gavofyork It is the case. The "skip" button is shown in the "create an account" step.

[jacogr]

Would have preferred the labels/hint/text changes into FormattedMessage while we are in the component. (Saves work later, especially when adding new features).

Not a crisis here though, so will just comment on it - small enough change overall.

[jacogr]

Additional prop verification issues introduced:

vendor.js:6509 Warning: Failed prop type: Invalid prop `showFirstRun` of type `number` supplied to `Container`, expected `boolean`.
    in Container (created by Application)
    in Application (created by Connect(Application))
    in Connect(Application) (created by RouterContext)
    in RouterContext (created by Router)
    in Router (created by MainApplication)
    in MainApplication
    in IntlProvider (created by ContextProvider)
    in ContextProvider

&

vendor.js:6509 Warning: Failed prop type: Invalid prop `visible` of type `number` supplied to `FirstRun`, expected `boolean`.
    in FirstRun (created by Connect(FirstRun))
    in Connect(FirstRun) (created by Container)
    in div (created by ParityBackground)
    in ParityBackground (created by Connect(ParityBackground))
    in Connect(ParityBackground) (created by Container)
    in Container (created by Application)
    in div (created by Application)
    in Application (created by Connect(Application))
    in Connect(Application) (created by RouterContext)
    in RouterContext (created by Router)
    in Router (created by MainApplication)
    in MainApplication
    in IntlProvider (created by ContextProvider)
    in ContextProvider
    in AppContainer

[derhuerst]

Additional prop verification issues introduced:

This should only be because there's still 0/1 in your localStorage. After reload, this should be set to false/true and therefore gone.

Edit: can you confirm?

[coveralls]

Changes Unknown when pulling bbcae3d on jr-first-run into ** on master**.

[jacogr]

Yes, you are right, it is a once-off