[ADP-3368] Use flakes in E2E, remove default.nix, shell.nix (#4644)

This PR remove `shell.nix` in favor of flakes

- [x] remove `default.nix` 
- [x] remove `shell.nix`
- [x] remove `test/e2e/shell.nix`
- [x] move e2e needs in the main flake

.gitignore

@@ -78,3 +78,4 @@ lib/wallet-benchmarks/data/membench-snapshot
 
 ## Local cluster swagger golden actual
 lib/local-cluster/data/swagger.json.actual
+test/e2e/.direnv/flake-profile*

nix/haskell.nix

@@ -110,7 +110,17 @@ CHaP: haskell-nix: nixpkgs-recent: nodePkgs: haskell-nix.cabalProject' [
         filter = haskell-nix.haskellSourceFilter;
       };
 
-      shell = {
+      shell =
+        let
+          # To update gemset.nix, run:
+          #   nix-shell --arg bins false --run bundix
+          gems = pkgs.bundlerEnv {
+            name = "gems-cardano-wallet-e2e";
+            gemdir = ../test/e2e;
+            ruby = pkgs.ruby_3_1;
+          };
+        in
+      {
         name = "cardano-wallet-shell${lib.optionalString config.profiling "-profiled"}";
         packages = ps: builtins.attrValues (haskellLib.selectProjectPackages ps);
         tools = {
@@ -130,6 +140,11 @@ CHaP: haskell-nix: nixpkgs-recent: nodePkgs: haskell-nix.cabalProject' [
           nodePkgs.cardano-node
           cardano-addresses-cli.components.exes.cardano-address
           bech32.components.exes.bech32
+          # for e2e tests
+          gems
+          gems.wrappedRuby
+          pkgs.bundix
+          pkgs.screen
         ]) ++ (with pkgs.buildPackages.buildPackages; [
           just
           pkg-config

test/e2e/.envrc

@@ -8,7 +8,7 @@ else
     # to prevent bootstrapping problems.
     # It's definitely better to use lorri, because direnv won't
     # be fast like this.
-    use nix
+    use flake
 fi
 
 # Source a user-specific config in .envrc-local at the project