USAGE readme issues

[pzaborowski]

the link on the:
https://github.com/opengeospatial/bblock-template/blob/master/USAGE.md

called Set the additional register metadata properties in bblocks-config.yaml.

does not provide explanation what are that additional metadata.

[rob-metalinkage]

Actually we need to move docs to links to a documentation repository - possibly bblocks-examples? - people copying templates will always have stale documents.

We need a higher level view of these things - hoping the "user story" activity will define the starting point and best form for this.