Fix some outdated explanations in docker README

[jo4965]

Hello. I'm dmjo who loves Flare.
I really appreciate for developing such a nice node system.

I'm operating some of Flare observers now with dockerization
and found some mismatch between real operation and the docker README.

What is the problem?

1. Mismatch between README and Dockerfile
   • The README-docker.md file reads that both AUTOCONFIGURE_PUBLIC_IP and AUTOCONFIGURE_BOOTSTRAP is set to '0' as default.
   • Dockerfile, however, configures them as '1' when initializing.
   • Below is part of current Dockerfile which set them to '1'

ENV HTTP_HOST=0.0.0.0 \
    HTTP_PORT=9650 \
    STAKING_PORT=9651 \
    PUBLIC_IP= \
    DB_DIR=/app/db \
    DB_TYPE=leveldb \
    BOOTSTRAP_IPS= \
    BOOTSTRAP_IDS= \
    CHAIN_CONFIG_DIR=/app/conf \
    LOG_DIR=/app/logs \
    LOG_LEVEL=info \
    NETWORK_ID=costwo \
    AUTOCONFIGURE_PUBLIC_IP=1 \
    AUTOCONFIGURE_BOOTSTRAP=1 \
    AUTOCONFIGURE_BOOTSTRAP_ENDPOINT=https://coston2.flare.network/ext/info \
    EXTRA_ARGUMENTS="" \
    BOOTSTRAP_BEACON_CONNECTION_TIMEOUT="1m"

• I think this should be fixed in the way like this PR or the other way (set to '0' in Dockerfile).

2. Some explanations in configuration are outdated.
   • Coreth v0.8.14 deprecated some of the configuration flags for eth_apis containing public- and private-.
   • AFAIK, the latest version of go-flare is now using Coreth v0.8.16 so the configurations should be changed.
   • You can find the information in the link and the picture I attached below

[aljazs-flare]

Thank you for finding and reporting these issues. Will need review from someone else from the team to verify those Coreth options as I'd say I'm not familiar enough with it.
Other than that looks just fine.