Add badge to pipeline readme template that dynamically shows if pipeline official or not

Description of feature

Background

As nf-core is so popular, many developers are using the nf-core template for their own pipelines.

Despite the more recent customisation options with nf-core pipelines create, many people still opt for the fully fledged template with nf-core branding (in some cases because they are considering proposing adding to nf-core after it's finished).

This can lead to confusion for the wider user-community when they come across a pipeline that has the nf-core branding, with an nf-core logo, but then cannot find the pipeline (nor it's documentation) on the website nor on slack.

Propose

I suggest we have a markdown-badge on the template, that (somehow) dynamically detects whether the repo the badge is on, is from an official accepted nf-core pipeline or not.

Implementation

I don't have a specific suggestion, but there are lots of different services online:

• https://github.com/marketplace/actions/dynamic-badges
• https://dynamic-badge-formatter.demolab.com/
• https://css-tricks.com/adding-custom-github-badges-to-your-repo/

Otherwise @ewels and @mashehu had suggestions here:

https://nfcore.slack.com/archives/C072TAN9RDE/p1756671866369489?thread_ts=1756632805.240339&cid=C072TAN9RDE

No specific file, test, or implementation entry point is named. Start by locating the nf-core pipeline README template and reviewing how official pipelines are identified; define a reliable badge mechanism and verify it distinguishes accepted nf-core pipelines from other repositories without misleading users.