container: plugins: root: fix example3()'s shell

The spawned shell needs its sourced environment and aliases.

Resolves:

  sh: line 1: dfi: command not found
  Error in <TRint::HandleTermInput()>: std::runtime_error caught:
          FILE = "/home/business/docker-finance/plugins/root/example.cc"
          LINE = 125
          WHAT = "command failed"

container/plugins/root/example.cc

@@ -122,7 +122,10 @@ void example3()
 
   auto exec_cmd = [&make_cmd](const std::string& cmd) {
     // shell 0 = success
-    THROW_IF(common::exec(make_cmd(cmd)), std::runtime_error, "command failed")
+    THROW_IF(
+        common::exec("bash -i -c '" + make_cmd(cmd) + "'"),
+        std::runtime_error,
+        "command failed")
   };
 
   std::cout << "\nImporting journals...\n";