[TT-16946][TT-16951] feat(ci): FIPS base image for EE/FIPS Docker builds (release-5.12) (#7977)

$(gh pr view 7977 --repo TykTechnologies/tyk --json body -q .body)

**Related Tickets:**
- [TT-16946](https://tyktech.atlassian.net/browse/TT-16946)
- [TT-16951](https://tyktech.atlassian.net/browse/TT-16951)

[TT-16946]:
https://tyktech.atlassian.net/browse/TT-16946?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ
[TT-16951]:
https://tyktech.atlassian.net/browse/TT-16951?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: buger