Add specialized scripts and functions to app

In main.ts is ```ts ipcMain.on("execute-ast", async (event: IpcMainEvent, ast: ScriptNode) => ... ``` It has the option to run a preload script: ```ts const fullCommand = config.preloadScript ? ${config.preloadScript} && ${command} : command; ... ``` however, if you look at the demos like tablecho.sh or sql-html-table.sh and as explained in the README there are functions and shell scripts that are required for these modules to work as expected. I'd like to come up with some manner of including these functions and scripts in the tool itself so people do not need to add them to their own dotfiles or bin directories. Please come up with a solution.