oauth: extend state cookie lifetime and fix post-signup-redirection after OAuth flow
Created by: unknwon
This PR includes two changes:
- Extend OAuth state cookie lifetime from 2 minutes to 15 minutes, because 2 minutes is not generally enough if the user encounters receive OTP from emails. Fixes https://sourcegraph.atlassian.net/browse/COREAPP-215
- Fix redirection to welcome page on cloud after OAuth flow by appending
redirect
query parameter to the OAuth authentication URL, which will be consumed by our backend upon user completing the OAuth flow. Fixes https://sourcegraph.atlassian.net/browse/COREAPP-216
Co-authored-by: Milan Freml [email protected]