feat: handle `token: true` inside overrides

[sandros94]

Currently the token override only accepts a string, undefined or false. I should also implement true and object.

Cases:

• token === undefined: try auth > current db > default db
• token === string: use string as token
• token === true: try current db > default db auth
• token === false: don't use any tokens
• token === object: use as basic auth

[sandros94]

implemented with https://github.com/Sandros94/nuxt-surrealdb/commit/2ed09c290c85b5497e39262566767151d6f3e0e9