argv: move options_only to cli/args

[GauthamGoli]

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#5730

[MikeMcQuaid]

Looks good! brew style is failing.

[GauthamGoli]

@MikeMcQuaid Fixed styles.

[MikeMcQuaid]

Thanks again @GauthamGoli!

[GauthamGoli]

This implementation is buggy and we would revert it;

Lets say I pass -v switch, then Homebrew.args would have v?=true, verbose?=true
and Homebrew.args.options_only would return both [-v, --verbose] which is wrong,
where as ARGV.options_only correctly returns [-v]