Update the Web scraping basics for JavaScript devs course

[honzajavorek]

Per discussion with @mnmkng, once #1319 is done, I should go through the JavaScript web scraping course for beginners and do a 'quick' check with at least basic fixes, so that it is presentable. I'm opening this issue for planning and tracking the work.

Known issues

• Update Academy's approach to setting up a Node.js project #947
• Clearly distinguish the beginner course from a 'quick start' #948
• Teach making requests in a consistent way #950

Goals

• Rename the JavaScript course to "Web scraping basics for JavaScript devs" feat: rename the JS course #1551
• Clearly distinguish the course intro from the rest and align it with the Python course
• Re-structure the course so that it's a flat list of numbered lessons
• Re-read the whole course and fix what can be quickly fixed
• Remove some parts which are relevant only for people who are completely new to coding
• De-duplicate images between the two courses

Non-goals

• There's no time to spend effort on adding exercises
• There's no time to fully align the lessons with the Python course and create the same polished 'story arc', as in going from simple scripts towards a framework and the platform