[Private deployment] Environmental variable rationality

[evanlong-me]

1. Private deployment should not verify the environment variable POLAR_WEBHOOK_SECRET.

2. Private deployment can optionally verify either GitHub or Google authorization methods.

3. Missing Vercel one-click deployment entry.

[llanesluis]

The 1. is specially true to be able to test the production environment locally. Building the app fails because it's checking for this env var. I had to manually patch the API Route to test the prod environment.

[evanlong-me]

Yep

1. I only have Strpie
2. I think private deployment doesn't need to collect the payment from oneself 🤣