"Add" button to create new textblocks

[GeorgeCiesinski]

Description:

Add a button to create new textblocks.

Solution:

1. An add button is placed on the root window under the textblocks display. Clicking this opens a toplevel widget with:

• A dropdown list containing the directories setup in the config file & label naming the dropdown
• A text input field for the shortcut & label naming the text input field
• A text input field for the textblock & label naming the text input field
• A save button

2. Clicking save checks if both fields are filled out. If yes, it creates a new file in the selected directory & names it the user input for the shortcut input field, and saving the textblock text within this file.
3. Ascertain that the text file has been created.
4. Automatically reload textscript.

[GeorgeCiesinski]

Added toplevel widget in commit 5fe1d97

[GeorgeCiesinski]

Created widget layout in commit cdde09e