Remove Known Issues

[nils-work]

These items in the Known Issues section (as at v1.31.0) appear to have been resolved or are no longer required and can be removed. The DCR specs are not perfectly aligned to the rest of the Standards but they also include some field names defined in upstream specs.

Issue	Description
Register APIs use local version of common definitions	The Register APIs use a locally defined version of common schema definitions such as ResponseErrorList for error responses. These need to be updated to reference common swagger specifications inherited by the Common Swagger spec.
Register APIs use different field type definitions	The Register APIs define their own field types that are not consistent with the Common Field Types defined in the data standards. As part of porting the Register standards across to the primary data standards, the field types need to be re-aligned to use the common field type definitions. For example, string (data-time) should be changed to DataTime and integer(int32) should be changed to PositiveInteger.
DCR and Register Swagger naming conventions	The DCR and Register naming conventions are not consistent with the broader data standards. Field names should be standardised to camelCase and snake_case inline with the data standards

[nils-work]

The field format changes above were largely addressed in #546 - Update Register and DCR Swagger specs to use Common Field Types.