🚀 Feature: Add information about the length of the talks on the `/speak` page

### Bug Report Checklist - [x] I have pulled the latest `main` branch of the repository. - [x] I have [searched for related issues](https://github.com/JoshuaKGoldberg/boston-ts-website/issues?q=is%3Aissue) and found none that matched my issue. ### Overview The `/speak` page should contain information regarding the length of the talks, specifically that the main speaker's talk duration should fit within 20 minutes, and the lightning talk capped at 10 minutes. One suggestion is to place it as a subordered list under the first bullet, "Present a dry run of your talk the week before, so we can check it for accessibility issues and make sure it runs the expected duration", as it seems like the information follows "expected duration" well. ### Additional Info _No response_