Invalidate file-cache when client schema_version is greater than records schema_version in document store

When Client has been upgraded and record schema has been changed, it is typically required that the file-cache is manually removed, so that DDI records are mapped to new record schema and updated to Document Store. We could use the schema_version attribute known by the Client and compare it with Document Store records schema_version attribute to automatically invalidate file-cache and thus process all records regardless of their modification datestamps in filesystem.

Also, in order for this to work, the records schema_version attribute must always be updated when schemas have changed.