More verbose documentation

[rgov]

The README file is a pretty terse and seems to presume a level of familiarity with the project already.

1. It seems I need to use project.dynamic = ["version"] for this to work in the first place, which is not mentioned.

2. What is the relationship between this project and setuptools-scm? Am I supposed to be familiar with the latter to use this?

3. It wasn't immediately clear whether the build hook plugin and metadata plugin are optional or not (they are optional).

   The build hook plugin is not really described; it just says, "The build hook plugin name is vcs" and proceeds to give a configuration example. It apparently generates a version file, but it was an unclear to me whether this was mandatory or not.

   The metadata plugin is described as "inserting VCS data (currently the commit hash) into metadata fields other than version" but it only allows it to be interpolated into project.urls which maybe could be called out more explicitly.

[ofek]

I would very much appreciate assistance with that!