nixos/packetbeat: Add packetbeat module

[lejonet]

Motivation for this change

Adds a packetbeat module so that it can be configured with
freeform settings. Made with big help from @aanderse and
@infinisil.

We have the packetbeat package in nixpkgs for some time, but no module, so I decided to make one. It uses the freeform module concept.

Remade PR after screwing up the prior PR with a botched rebase.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[lejonet]

@infinisil here's the config again:

packetbeat = {
    enable = true;
    package = pkgs.packetbeat7;
    settings = {
      name = config.networking.hostName;
      packetbeat = {
        interfaces = {
          device = "ens3";
          type = "af_packet";
          ignore_outgoing = true;
        };
        protocols = {
          tls = {
            ports = [ 443 993 995 5223 8443 8883 9243 ];
            send_certificates = true;
            include_raw_certificates = false;
            include_detailed_fields = true;
            fingerprints = [ "md5" "sha1" "sha256" ];
          };
        };
      };
      output = {
        elasticsearch = lib.mkForce {};
        file = {
          path = "/var/log/packetbeat";
          filename = "packetbeat.log";
          rotate_every_kb = "102400";
          number_of_files = "20";
        };
      };
      fields = {
        env = "utility";
      };
      processors = [ "add_host_metadata: ~" ];
    };
  };

[aanderse]

@lejonet I think this looks good 👍 I'll defer to @infinisil for final approval and merge, though.

[stale]

I marked this as stale due to inactivity. → More info

[lelongg]

Is this ready to be merged ?

[FliegendeWurst]

Suggested change

with lib;

Use specific inherits or add lib..

[FliegendeWurst]

Suggested change

	package = mkOption {
	type = types.package;
	default = pkgs.packetbeat;
	defaultText = "pkgs.packetbeat";
	example = literalExample "pkgs.packetbeat7";
	description = ''
	The packetbeat package to use
	'';
	};
	package = mkPackageOption pkgs "packetbeat" { };

[FliegendeWurst]

Suggested change

	${cfg.package}/bin/packetbeat \
	${lib.getExe cfg.package} \