Update language in network and community-specific ads

[cellio]

We have ad templates for both the network and specific communities. (Also specific questions, which this issue isn't about.) I'd like to add a little more "why" to the language in these two templates.

Proposals:

Network ad:

Codidact Open-source, non-profit Q&A and more Run by the community it serves Join our communities or build your own on codidact.com

Per-community ad:

(logo) on codidact.com Open-source, non-profit Q&A about (topic) Run by the community it serves Help us build a great community together

And then, for both, the URL at the bottom as now.

[cellio]

Text is in app/helpers/advertisements/codidact_helper.rb and community_helper.rb . I can make the easy fix proposed here, but that will still leave references to our network in the starting code for other deployments. They can edit these files too, of course. Is a more general solution possible? I guess the runtime code would need to "know" the name and URL of its network, so maybe that's making things too complicated?