Authenticate with Discogs via OAuth 1.0a and read/manage an authenticated user's collection folders and wantlist

Steps

1. Register an application on Discogs to get a consumer key and consumer secret for the OAuth 1.0a flow
2. Request an unauthorized request token from `https://api.discogs.com/oauth/request_token`, signed per OAuth 1.0a, then redirect the user to `https://www.discogs.com/oauth/authorize` to approve access
3. Exchange the authorized request token (plus the verifier returned after user approval) for a long-lived access token and token secret at `https://api.discogs.com/oauth/access_token`
4. Use the resulting OAuth 1.0a-signed access token/secret pair on subsequent requests to list the authenticated user's collection folders and the releases inside a given folder
5. Read the user's wantlist via its dedicated endpoint (paginated), and add or remove releases from it using the corresponding write calls now that the request is authenticated as that user
6. For collection writes (adding a release to a folder, moving it between folders, rating it), use the folder-scoped release endpoints, since collection organization is folder-based rather than a single flat list