Replace the full PR modernization checklist template with a link to wiki

[droumis]

Since the NF SDG is done, the modernization checklist is more of an optional resource and may be confusing to show the whole thing without context

[github-actions[bot]]

Your changes were successfully integrated in the dev site, make sure to review the pages of the projects you touched before merging this PR: https://holoviz-dev.github.io/examples/. You can also download an archive of the site from the workflow summary page which comes in handy when your dev site built was overriden by another PR (we have a single dev site!).

[maximlt]

Agree with that. Do you want to put the sentence you added as a Markdown comment (<!-- foo -->)? I don't have any strong preference.

[github-actions[bot]]

Your changes were successfully integrated in the dev site, make sure to review the pages of the projects you touched before merging this PR.