fix: Do not require auth on CORS preflights

[berezovskyi]

Description

Do not require auth on CORS preflights. Also allows the ignore flag to be overridden too.

Checklist

• This PR adds an entry to the CHANGELOG. _See https://keepachangelog.com/en/1.0.0/ for instructions. Minor edits are exempt.
• This PR expects some manual changes to the generated code. The needed changes are detailed in the CHANGELOG entry.
• This PR was tested with at least one code generation, resulting in a working OSLC server.
• This PR does NOT break the user block code

Issues

Fixes #214

(use exactly this syntax to link to issues, one issue per statement only!)

[berezovskyi]

And I think your recent regen for 6.0 wiped out oslc-op/refimpl@3500741 and maybe some other changes.