i2p: get rid of duplicate Java Service Wrapper

[Luflosi]

Motivation for this change

The definition of Java Service Wrapper in i2p is identical to the java-service-wrapper package except that the latter also executes the test suite, which requires some extra dependencies.
The java-service-wrapper package was actually added in #67824 to move the definition from the i2p package into a separate package. While it was added as a separate package, it was never removed from i2p. This commit fixes that.

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 packages 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/)
• 21.11 Release Notes (or backporting 21.05 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
• Fits CONTRIBUTING.md.

[r-rmcgibbo]

Result of nixpkgs-review pr 134432 at 027a862d run on x86_64-linux 1

1 package built successfully:

• i2p

5 suggestions:

• warning: unclear-gpl

  gpl2 is a deprecated license, please check if project uses gpl2Plus or gpl2Only and change meta.license accordingly.

  Near pkgs/tools/networking/i2p/default.nix:48:5:

     |
  48 |     license = licenses.gpl2;
     |     ^
  

• warning: missing-phase-hooks

  installPhase should probably contain runHook preInstall and runHook postInstall.

  Near pkgs/tools/networking/i2p/default.nix:20:3:

     |
  20 |   installPhase = ''
     |   ^
  

• warning: build-tools-in-build-inputs

  which is a build tool so it likely goes to nativeBuildInputs, not buildInputs.

  Near pkgs/tools/networking/i2p/default.nix:12:3:

     |
  12 |   buildInputs = [ jdk ant gettext which ];
     |   ^
  

• warning: missing-patch-comment

  Consider adding a comment explaining the purpose of this patch on the line preceeding.
  Near pkgs/tools/networking/i2p/default.nix:13:15:

     |
  13 |   patches = [ ./i2p.patch ];
     |               ^
  

• warning: missing-phase-hooks

  buildPhase should probably contain runHook preBuild and runHook postBuild.

  Near pkgs/tools/networking/i2p/default.nix:15:3:

     |
  15 |   buildPhase = ''
     |   ^
  

[Luflosi]

I resolved the conflict and improved the description and commit message.

[Luflosi]

Thank you 🎉.