Improve UI performance documentation

Based on UI perf diary homework study, participants noted there were several things they would like to improve on the UI performance documentation

- Many used DevTools docs and performance profiling docs to learn about DevTools features and performance profiling
- Users would like to see more screenshots, examples, and interactive videos like Widget of the Week videos (P2, P8) and DevTools Inspector doc page
- For their own UI perf issues, they would usually start from Google->Stackoverflow->Flutter docs (P4)
- Request topics: UI testing (P3), Android set up (P4), GPU debugging (P6)
- Users would like to incorporate more docs and tooltips in DevTools, e.g. more information icons “!” links to docs

We could fix this by
- [ ] Create documentation and tutorials for common UI performance issues (animation, large list, images, web)
- [ ] Create more interactive documentation with screenshots, videos, and tutorials of DevTools
- [ ] Create DevTools of the Week video to introduce different DevTools features, visualization, and performance best practices.
- [ ] Add links to docs or tooltips using “!” on DevTools
- [ ] Create examples and tutorials using sample apps and homework tasks to teach users how to use DevTools