Folder structure and name

[kbjarkefur]

Can I suggest this folder structure:

- 0-intro-to-programming/
- 1-foundations-of-programming/
    - 1-types-and-syntax/
    - 2-control-flows-and-functions/
    - 3-numpy-and-pandas/
    - 4-api-and-dataviz/
- 3-advanced-topics/
    - placeholder.md

1. No spaces in folder names makes prettier URLs.
2. Will expand well for the future

[kbjarkefur]

I can fix this myself @luisesanmartin if this is OK with you.

[luisesanmartin]

@kbjarkefur yes, that's ok

[kbjarkefur]

renamed in 10d92be