v6 Strike REST API

[dfaller]

Create new v6 Strike REST APIs. There are no changes from v5. Create new v6 versions of all Strike-related JSON schemas. Look at changing POST /v6/strikes/ so that user does not submit name (Scale-generated instead from title). Add docs to new v6 section of the REST API docs.

[JohnPTobe]

auto generate name from title field, ignore user specified name if present.
write util for converting title to name that works like seed convention:
just lower case letters and dashes
limit to 30ish characters (whatever the database field allows)
append uuid if conflicts with another name