SchemaIOProvider should differentiate between read-only and write-only configuration

[damccorm]

SchemaIOProvider should formally differentiate between common, read-only and write-only configuration, it's confusing to combine them all into one config object when it's not needed. The only place its needed is in SQL, so we should do it there.

Imported from Jira BEAM-10709. Original Jira may contain additional context.
Reported by: bhulette.