Spike: Qt 6 Benchmarking in Foundation area

For Qt 6 many public and private classes has been revamped for

• simplicity
• performance
• memory utilization

While many of the efforts had some internal/wip benchmarks to verify the efforts, it is now important to shape those benchmarks into something we can refer to.

This spike is about identifying areas where we need to create/update/verify benchmarks.

For areas where we need to create new benchmarks, new issues will be created. The purpose of this spike is to have a full understanding on the areas we want to highlight and talk about, preferrably with some initial input already to include into our Qt 6 materials.