Rename folders in the repo

[PinkShnack]

We have two main types of code that people will share:

1. scripts
2. functions/classes

These should be in a folder called code_sharing perhaps. So:

code_sharing
    |
    |
    scripts
        |
        |
        rtdc_scripts
            |
            print_av_brightness
                |
                |
                requirements.txt
                print_av_brightness.py  
        |
        file_opening_scripts
    functions
        |
        |
        rtdc_functions
        plotting_functions
            |
            cool_plot_func
                |
                |
                requirements.txt
                cool_plot_func.py
                test_cool_plot_func.py

This might be overkill. Could have all just in code_sharing/theme1/filename.py...