Describe business value of features in specs

@charlierudolph This is a preview of what I'm planning to do with all specs. Wanted to get your feedback before I invest a lot of time into this.

This helps understand WHY the feature exists. The steps then explain HOW the feature works.
This also helps formulate the value of Git Town to teams better.
```
As a developer trying to extract commits from the main branch
I want to reminded that this command can only be run on feature branches
```
When there is no apparent so I don't see the reason to try to add one.