* fix(docker): warn instead of rejecting default or missing credentials
The entrypoint hard-reject from #4278 broke the container-first UX and
the repo's own scheduled e2e lanes (e2e-s3tests, mint boot rustfs-ci
images with default credentials and died at startup). Maintainer
decision: ship no baked-in credentials, warn instead of block.
- missing credentials: warn and start; wording accounts for the
RUSTFS_ROOT_*/MINIO_* alias sources the entrypoint does not inspect
- default rustfsadmin via env/CLI/file: warn and start; the warning
notes all-default pairs cannot derive an internode RPC secret
- malformed config stays fatal: source conflicts, unreadable files,
empty or whitespace-only values, flags missing their argument
- present-but-empty env vars now hit the empty-value hard failure
instead of running the binary with an empty root credential
- empty/default checks trim CR and blanks like the binary; files
without a trailing newline are no longer falsely rejected as empty
- the no-baked-credentials guard covers all four Dockerfiles, and the
test harness refuses hosts where /usr/bin/rustfs exists
- e2e-s3tests/mint move to non-default credentials (rustfsadmin-ci),
which also restores RPC-secret derivation for the multi-node lane
GHSA-68cw fail-closed RPC derivation (#4402) is untouched; helm stays
fail-closed by design.
* chore(docker): reword entrypoint comment flagged by typos check
Jose Meira