Update nix setup

Need to remove solr, because it has been dropped in nixos 23.11

nix/checks/configuration-test.nix

@@ -2,7 +2,7 @@
 let
   full-text-search = {
     enabled = true;
-    solr.url = "http://localhost:${toString config.services.solr.port}/solr/docspell";
+    backend = "postgresql";
     postgresql = {
       pg-config = {
         "german" = "my-germam";
@@ -24,7 +24,6 @@ in
 
   services.docspell-joex = {
     enable = true;
-    waitForTarget = "solr-init.target";
     bind.address = "0.0.0.0";
     base-url = "http://localhost:7878";
     jvmArgs = [ "-J-Xmx1536M" ];

nix/checks/default.nix

@@ -2,6 +2,5 @@
 {
   imports = [
     ./configuration-test.nix
-    ./solr.nix
   ];
 }

nix/checks/solr.nix

@@ -1,41 +0,0 @@
-{ config, pkgs, lib, ... }:
-
-# This module sets up solr with one core. It is a bit tedious…. If you
-# know a better solution, please let me know.
-{
-  nixpkgs.config = {
-    permittedInsecurePackages = [
-      "solr-8.6.3"
-    ];
-  };
-
-  services.solr = {
-    enable = true;
-  };
-  # This is needed to run solr script as user solr
-  users.users.solr.useDefaultShell = true;
-
-  systemd.services.solr-init =
-    let
-      solrPort = toString config.services.solr.port;
-      initSolr = ''
-        if [ ! -f ${config.services.solr.stateDir}/docspell_core ]; then
-          while ! echo "" | ${pkgs.inetutils}/bin/telnet localhost ${solrPort}
-          do
-             echo "Waiting for SOLR become ready..."
-             sleep 1.5
-          done
-          ${pkgs.su}/bin/su -s ${pkgs.bash}/bin/sh solr -c "${pkgs.solr}/bin/solr create_core -c docspell -p ${solrPort}";
-          touch ${config.services.solr.stateDir}/docspell_core
-        fi
-      '';
-    in
-    {
-      script = initSolr;
-      after = [ "solr.target" ];
-      wantedBy = [ "multi-user.target" ];
-      requires = [ "solr.target" ];
-      description = "Create a core at solr";
-    };
-
-}