Add documentation for batch posting in the location URL schemes

[cookeac]

There is substantial discussion of how \batch\ URL schemes and the return results should work in issue #154 and the technical minutes during 2021, but it is not documented. We should create a markdown specification for use in the \docs folder and explain how the batch endpoints were designed to return a 2xx result code and the results object (with results for each item in the array of resources posted). A non-success result code would be returned if the array could not be parsed, or was of the wrong type entirely, or other error such as authentication problem.