Support for `topic` channels

[edmundmiller]

Wondering if we could get support for topic channels.

https://www.nextflow.io/docs/latest/channel.html#topic

Mainly for nf-core/modules

Docs: https://www.nextflow.io/docs/latest/channel.html#topic Example in pipelines: https://github.com/nf-core/nascent/pull/150/files nf-core/modules issues: https://github.com/nf-core/modules/issues/5834 https://github.com/nf-core/modules/issues/4517