Disable updating fields. module will only create field
changes in this PR:
- disable updating fields, existing fields in coveo will not be updated.
- module can only create fields from search_api yaml config.
- move the error handling in doRequest function.
- If the coveo error code is FIELD_DOES_NOT_EXIST do not log error message. the error is expected and will only appear when retrieving the coveo field and it does not exist.