IGNITE-24814 Allow overriding variables in start script

[valepakh]

https://issues.apache.org/jira/browse/IGNITE-24814

[PakhomovAlexander]

Code Review

Overall this is a solid, well-structured change. Two suggestions worth addressing:

1. Unknown --* arguments are silently swallowed

In the Linux parse_args, any unrecognized argument (e.g., a typo like --nde-name) is silently shifted away without any feedback. This makes misconfiguration hard to debug. Consider emitting a warning for unrecognized --* flags:

--*)
    echo "Warning: unknown option '$1'" >&2
    ;;

Same applies to the Windows :parseArgs — unrecognized --* args silently fall through to shift.

2. No --help flag

The script now accepts 5 new CLI flags (--node-name, --work-dir, --log-dir, --config, --extra-classpath) but provides no usage message. A --help / -h case in the parser printing available options would be valuable for discoverability, especially since these flags don't appear to be documented anywhere else in the PR.

[PakhomovAlexander]

see comment

[valepakh]

Done