Add OCO_HOOK_AUTO_UNCOMMENT to environment configuration

[barathvk]

The new option OCO_HOOK_AUTO_UNCOMMENT in #494 is not exposed as en environment variable. This PR reads this value from the environment, like other configuration values

[di-sukharev]

This fix is needed, and typecheck and unit tests pass, but the resulting merge fails Prettier. Please format src/commands/config.ts and add one config test confirming that OCO_HOOK_AUTO_UNCOMMENT from the environment is parsed as a boolean.