Make frontend changes to accomodate min/max encoder quality changes in 5.5

[DenisTensorWorks]

Component your feature request relates to

• Frontend library
• Frontend UI library

Problem your feature solves? Please describe.
We need to accomodate for the move to min/max encoder quality scale instead of min/max QP cvars.
Ensure we still send the old MinQP/MaxQP messages for backwards compatibility.

Internal reference: UE-220968

[lukehb]

@mcottontensor When you get round to this, let's have a discussion. But basically some internal discussion of changing these on the plugin side, which has some flow on effect to the frontend.