- Removes backward compatibility
for legacy end points `/models` & `/routes`
- Removes `legacyExplorer` flag which
enabled these routes
- Update related tests & tests using the
legacyExplorer flag
*Re-mapping `updateAttributes` endpoint to use
`PATCH` and `PUT`(configurable) verb
*Exposing `replaceById` and `replaceOrCreate` via
`POST` and `PUT`(configurable) verb