Solved Fetching the ports tree over git

[dch]

Please see https://people.freebsd.org/~dch/git.html for a work-in-progress guide to fetching ports tree via git.

- this is largely based off the committer's guide
- you're welcome to add comments here
- I will roll them back into the above docs, and eventually remove my wip doc

I am aware there are many alternative clients, but for the moment let's keep this as simple as possible and not introduce unneeded complexity.

Thanks for your perseverance & flying FreeBSD