Fix ubi8-rust-builder to a specific sha or tag

[Maleware]

Currently, the ubi8-rust-builder-image get's build once a day, every time we build the rust builder image our operator images can't be reproduced to the exactly same image as before.

As a consequence, we can't reproduce previous operator releases as they were.

Suggestion:
Fix ubi8-rust-builder to a specific Tag for at least releases. Thus we need in the build process an option to specify imags.