Customizeable Better-Auth Providers

[aidankmcalister]

Idea

Add the option to specifiy what Better-Auth providers you want enabled in the builder and CLI, like with

    socialProviders: {
      github: {
        clientId: process.env.GITHUB_CLIENT_ID as string,
        clientSecret: process.env.GITHUB_CLIENT_SECRET as string,
        scope: ["read:user", "user:email", "read:org", "repo"],
      },
    },