nixos/nextcloud: Add default for option hostName

[onny]

Description of changes

Sets default hostName to

localhost

``` if config.networking.domain != null then "nextcloud.${config.networking.fqdn}" else "nextcloud.${config.networking.hostName}" ```

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.11 Release Notes (or backporting 22.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[Ma27]

Setting an fqdn to a hostname by default seems wrong to me. Perhaps we should only set the default if networking.domain != null?

[onny]

@Ma27 would be default value "localhost" for hostName okay?

[Ma27]

would be default value "localhost" for hostName okay?

I'm sorry, I fail to understand the motivation behind that: that's by default the only value in trusted_domains and in the most cases localhost isn't what you want there or in your reverse proxy.