Polykey integration into workflow

[brynblack]

Description

This PR integrates pk secrets env into the development shell. It also fixes an API issue regarding secrets used to authenticate with Cloudflare's API. It replaces the AUTH_... secrets with an API token.

Tasks

• [x] 1. Replace . ./.env with pk secrets env ...
• [x] 2. Fix API security issue

Final checklist

• [x] Domain specific tests
• [x] Full tests
• [x] Updated inline-comment documentation
• [x] Lint fixed
• [x] Squash and rebased
• [x] Sanity check the final build