Add RefreshTokenScopes Config

[dmcinnes]

Related issue

Original discussion #370 discussed with @aeneasr

Proposed changes

This adds the RefreshTokenScopes to compose config to set which scopes will provide a refresh token on grant exchange. This defaults to "offline" and "offline_access". When empty all grant exchanges will provide a refresh token.

Checklist

• I have read the contributing guidelines
• I have read the security policy
• I confirm that this pull request does not address a security vulnerability. If this pull request addresses a security
  vulnerability, I confirm that I got green light (please contact [email protected]) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation within the code base (if appropriate)

Further comments

[CLAassistant]

All committers have signed the CLA.

[aeneasr]

Could you please sign the CLA? :)

[dmcinnes]

I’m working with my company’s legal people to see if I can sign it.

…

On Tue, Jul 2, 2019 at 4:12 AM hackerman ***@***.***> wrote: Could you please sign the CLA? :) — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#371?email_source=notifications&email_token=AAAEBLK6LBRXBV3YTVVVNGLP5MZZHA5CNFSM4H37FO52YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODZA5ICA#issuecomment-507630600>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAAEBLIYI6SV7RIAZPFBXZ3P5MZZHANCNFSM4H37FO5Q> .

[aeneasr]

Any updates? :)

[dmcinnes]

Unfortunately still waiting on the last level of approval.

[dmcinnes]

Hello @aeneasr, I've signed the CLA.

[aeneasr]

Thank you! Just came back from a vacation so sorry for the delay :)