Feature: better display code for stack/workspace

[DivadNojnarg]

In addition to copy to clipboard, would be convenient to have a modal window showing the code (ex generate_server.stack):

Note:

• We don't necessarily need a specific widget editor like shinyAce...
• Code output of a filter block is quite ugly and would need to be cleaned: eval(call("==", colname, "aaa")).

observeEvent(input$copy, {

        code <- generate_code(vals$stack) |>
          deparse() |>
          as.character() |>
          as.list()
       
       # Modal
        showModal(
          modalDialog(
            title = "Stack code",
            size = "l",
            shinyAce::aceEditor(
              outputId = session$ns("ace"),
              selectionId = "selection",
              value = styler::style_text(code, strict = TRUE),
              mode = "r",
              wordWrap = TRUE,
              readOnly = TRUE,
              placeholder = "Show a placeholder when the editor is empty ..."
            )
          )
        )
       
       # Copy to clipboard
        session$sendCustomMessage(
          "blockr-copy-code",
          list(
            code = generate_code(vals$stack) |>
              deparse() |>
              as.character() |>
              as.list()
          )
        )
      })

We may not need shinyAce.