Remove jdtls, it's in nixpkgs as well

packages/jdtls/default.nix

@@ -1,34 +0,0 @@
-{ stdenv, bash, fetchurl, jdk17, ... }:
-
-stdenv.mkDerivation rec {
-  pname = "jdtls";
-  version = "1.13.0";
-  src = fetchurl {
-    url = "http://download.eclipse.org/${pname}/milestones/${version}/jdt-language-server-${version}-202206301721.tar.gz";
-    sha256 = "WimtKNdl9AgQaoexR7I5aWlCoR8i+VDFLcNxdvzpz8k=";
-  };
-  sourceRoot = ".";
-  buildPhase = "true";
-  installPhase = ''
-    mkdir -p $out/share/java/jdtls
-    mv config_* features plugins $out/share/java/jdtls
-    mkdir $out/bin
-    cat >$out/bin/jdtls <<HERE
-    #!${bash}/bin/bash
-    tmp_dir=\$(mktemp -d /tmp/jdtls.XXXXX)
-    cp -R $out/share/java/jdtls/config_linux \$tmp_dir
-    chmod -R u=rwX \$tmp_dir
-    trap "{ rm -rf \$tmp_dir; }" 0
-    ${jdk17}/bin/java \
-      -Declipse.application=org.eclipse.jdt.ls.core.id1 \
-      -Dosgi.bundles.defaultStartLevel=4 \
-      -Declipse.product=org.eclipse.jdt.ls.core.product \
-      -noverify \
-      -Xms1G \
-      -jar $out/share/java/jdtls/plugins/org.eclipse.equinox.launcher_*.jar \
-      -configuration "\$tmp_dir/config_linux" \
-      "\$@"
-    HERE
-    chmod +x $out/bin/jdtls
-  '';
-}