Add NüschtOS Modules

[SuperSandro2000]

Notable things which I should really write down:

• LDAP/OAuth integration for services like Grafana, Matrix, Mastodon, Hydra, oauth2-proxy, Home-Assistant, Mailman https://search.xn--nschtos-n2a.de/?query=ldap https://search.xn--nschtos-n2a.de/?query=oidc
• Module to update PosgtreSQL in three steps https://search.xn--nschtos-n2a.de/?query=postgresql.upgrade
• Nextcloud integration for Memories and Recognize Apps https://search.xn--nschtos-n2a.de/?query=services.nextcloud
• Some recommended defaults for grafana, gitea, nextcloud, postgres, git, tmux, docker https://search.xn--nschtos-n2a.de/?query=recommendedDefaults

[cyntheticfox]

While it is the repository description, the entry feels a little too vague next to the other entries.

Adding some of those features like "with extra LDAP integration and easy pgsql upgrades" would do way more to distinguish the project from the other entries and from most NixOS modules and configurations.

I won't suggest those exact words though -- you can probably find better descriptors of what makes it different

[SuperSandro2000]

Took me a while but the readme should now be way more polished and we also integrated our options search into it. Can you take another look?

[cyntheticfox]

Er, I think my review wasnt very clear; the repo and project are good. The awesome-nix description text proposed in this PR is just vague -- it mentions having configurations and being opinionated, but doesn't say anything about the "what" the modules are, though that is in the PR description.

That'd be adding on to the text to make it something like

...Opinionated, LDAP-integrated, and shared-service NixOS modules.

or something like that to make it more specific