Update all the Markdown files for the S24 running of this lab

[NicMcPhee]

There's a lot here, so this is going to be a kind of annoying PR to review. The highlights:

• @kklamberty and I decided that since we now have all these automatic checks in places, the badges aren't really necessary since the green check or red x tells us what we want/need to know. Including and updating the badges does add a little friction, so we'll just remove them.
• I added a lot of detail about how to create a Personal Access Token specifically for this lab so that students can do the command line git work described in part one.
• I removed the historical notes about the change to main as I think that transition is mostly done now and people are a lot less likely to run into the old approach.
• Added a note about the need to add GitKraken to the organization in the facutly/TA todos. I never remember to do this and get burned at the start of the semester, so I thought it would be good to mention it.
• I attempted to document the new merge queue approach. This is probably the part I'm least confident about, and I may not really know what it looks like until we do it tomorrow in lab.

There were also a bunch of minor grammar fixes, updates, etc. I even found one dangling reference to IntelliJ IDEA, which I switched to VS Code. 😜

Closes #118

[NicMcPhee]

Thanks for the careful read through. Both of those are now fixed!