feat(chapter-1): understanding commits in Git

Revamps chapter one "Understanding Commits in Git". Pinging @cburgdorf for review.

Comments welcome!
- **The** first thing **we are** going to do is **take a closer** look at
- **Then, we are going to look into what those weird hashes, consisting of numbers and characters, that Git apparently produces quite often, are all about.**
-  The third sentence could use some rework. ""we're going to realize"" in that context should be "we will come to realize that". I am also wondering if that "we" is necessary. I mean it is not incorrect, but the way I see the reader-writer relationship is "we are going over this and this so that you, the reader, get this and that". But that might be just me and as I said it is not incorrect. It just depends what your intention is and how you want to use this
- **But first,** let's start with the long revision names we were talking about