Even though convert2rhel allows converting Scientific Linux 7 to RHEL in upstream, Red Hat has never supported it.

The BU feature for making this path supported has been closed recently (RHELBU-1494) because we've seen no demand for that and the distribution won't be supported after June 2024.

Acceptance criteria:

• The convert2rhel config file for Scientific Linux 7 is removed from the upstream repo https://github.com/oamg/convert2rhel/blob/main/convert2rhel/data/7/x86_64/configs/scientific-7-x86_64.cfg
• All mentions of Scientific Linux 7 being possible to convert is removed from the upstream repo (including the About section of the repo) and from the Confluence page
• The note "In addition to the above supported conversion paths, it is also possible to perform an unsupported conversion from Scientific Linux to RHEL." is removed from the supported conversions documentation