Add go devshell

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

hosts/common/shells/go/default.nix

@@ -0,0 +1,22 @@
+{ pkgs, ... }:
+pkgs.mkShell {
+  packages = with pkgs; [
+    go
+    gopls
+    go-tools
+  ];
+
+  shellHook = ''
+    export P10K_EXTRA_RIGHT_PROMPT_ELEMENTS=(
+      goenv
+      "''${P10K_EXTRA_RIGHT_PROMPT_ELEMENTS[@]}"
+    )
+
+    if git rev-parse --is-inside-work-tree &> /dev/null && ! grep -q "^\.go$" .gitignore .git/info/exclude; then
+      echo ".go" >> .git/info/exclude
+      export GOPATH="$(git rev-parse --show-toplevel)/.go"
+    else
+      export GOPATH="$(pwd)/.go"
+    fi
+  '';
+}