Add option to ONLY download the source code (no videos) for all courses

[connecteev]

After fixing #5 to also download source code of the course (if available), could we add another option to ccdown to ONLY download the source code (no videos) for all courses, using the same folder structure?

The reason for this is I have already downloaded all 136 courses under a subject, like https://codecourse.com/subjects/php
but they don't contain the source code. I would like to ONLY download the source code for php, laravel, etc courses under a subject, and merge it with the video files already downloaded. If they were contained in the same folder name, like 256-Build a Distraction Dashboard, it would be easier to merge the 2 folders together manually.

ccdown
✔ Do you want all courses? … no
✔ Choose "Y" if you want to search for a course otherwise choose "N" if you have a link for download … no
✔ Enter url for download. … https://codecourse.com/subjects/laravel-livewire
✔ Choose "Y" if you want to include the source code (if available), choose "N" if you don't want to include source code, choose 'C' if you ONLY want to download the source code ... code

Typing 'C' could autocomplete to 'code' and only download the source code for each course on the selection list. The folder structure sould be the same, and contain the source code files, like this:

• 238-Build a Podcast App/podcast.zip
• 256-Build a Distraction Dashboard/ distract.zip
• and so on