Parent: #384

Some env vars are not needed anymore, or they were added without needing to during the container updagre.

For example:

We do not have UDP and HTTP ports in the Index:

ENV UDP_PORT=${UDP_PORT}
ENV HTTP_PORT=${HTTP_PORT}

We are using the USER_ID to run the container and it's injected at runtime (not build time).

TORRUST_INDEX_RUN_AS_USER
RUN_AS_USER