SDK-2389 Provide alternative/simpler OAuth and SSO methods

[jhaven-stytch]

Linear Ticket: SDK-2389

Changes:

1. Adds new getTokenForProvider methods to B2C OAuth, B2B OAuth, B2B OAuth Discovery, and B2B SSO flows. This method allows developers to create "oneshot" login methods, similar to the iOS implementation, where we have a "start" flow that just returns a token, and can be combined/chained with the authenticate method. This makes configuring/using OAuth/SSO a bit simpler, as it removes the need for configuring activity result listeners and URL parsing the result.
2. Adds methods to workbench apps for testing
3. Updates OAuth tutorial to explain this new flow
4. Bumps version

Notes:

Checklist:

• I have verified that this change works in the relevant demo app, or N/A
• I have added or updated any tests relevant to this change, or N/A
• I have updated any relevant README files for this change, or N/A