Add test upload large files

[YuryHrytsuk]

Background

After migrating to Traefik v2 --> v3, the upload of large files (>1G) got broken due to some timeouts (HTTP Code 499) We caught this error only on STAG and it was too late.

We need to add a test in master so that we catch it early on.

People who have been fixing this bug @matusdrobuliak66 @mrnicegyu11. Talk to them for more info