Remove WCOSS2 stuff from issue template

[AlexanderRichert-NOAA]

Summary

Requests for installations on WCOSS2 should not be made here, but instead at https://github.com/NOAA-EMC/WCOSS2-requests/issues. Typically, package installation requests for spack-stack (this form) should be used for installing packages for testing on R&D systems prior to requesting those packages on WCOSS2 (Cactus/Dogwood), but the WCOSS2 installation requests themselves should be submitted separately at the provided link.

Testing

n/a

Applications affected

n/a

Systems affected

n/a

Dependencies

n/a

Issue(s) addressed

none

Checklist

• This PR addresses one issue/problem/enhancement, or has a very good reason for not doing so.
• These changes have been tested on the affected systems and applications.
• All dependency PRs/issues have been resolved and this PR can be merged.

[climbfuji]

Thanks!