Add “SAScienceCatalog” to metadataRepository code list

[hmaier-fws]

Request from @tpatterson1996 to add “SAScienceCatalog” to the dropdown list of repositories in metadata/repositories.

Add "SAScienceCatalog" to metadataRepository code list (https://mdtools.adiwg.org/#codes-page?c=adiwg_metadataRepository).

• Verify "codeName" and "description" with @tpatterson1996 and @mmheller
• Generate uuid value for "code" attribute
• Move issue to mdCodes

{
"code": "",
"codeName": "SAScienceCatalog",
"description": "Science Applications Science Catalog"
}