You can create new link types. This has been discussed on the forum and there are several answers here as well. This is a resource to start with: https://jazz.net/wiki/bin/view/Main/ProgrammaticLinkCreation . You can not remove link types, but you can hide them somehow. See https://jazz.net/library/article/1277 .

You can use the search field or any other search engine to search for hints. Some hits I got https://jazz.net/forum/questions/111761/can-i-create-a-custom-link-type-in-clm-401 . there have been a lot more discussions around this and you might want to search if you have additional questions.