[Feature] Improve build-and-benchmark parameterization

Improve build-and-benchmark workflow parameterization.

Background

The parameters are slightly confusing, as it relies on dropdowns, some text fields and their combinatory logic which is currently a bit opaque.

Proposed behavior

Clarify logic by removing some of the dropdowns and replacing them with simple checkboxes.

Something like this, will see what sticks:

• Text field: base image
• Checkbox: build core
• Checkbox: build untuned
• Run MIOpen tuning
• Run benchmarks
• Create MIOpen DB PR

Goals

Clear and concise workflow logic and user-friendly dispatch interface.