Background

Some of the environment variables will be deleted/replaced with better ones

Destructive changes in SIA v4.0.0

TOKEN_DIR deprecate (SIA v3) => 削除予定 (SIA v4)
Introduce features that uses the following keys as to enable/disable (all the bools)
- USE_TOKEN_SERVER
- DELETE_INSTANCE_ID
- ROLE_CERT_KEY_FILE_OUTPUT
- TOKEN_SERVER_REST_API
If you decide not to introduce features, refactor all the bool keys with prefix USE_ like USE_TOKEN_SERVER