Move Python and NodeJS pages

[nlsdvl]

Move the from Python and NodeJS pages from Howtos to Developer's sections.
Update the navigation menu, configure redirections from the old URLs to the new ones.

[arunkarthik-periyaswamy]

Hello @nlsdvl I would like to work on this issue. Can you please assign this issue to me?

[arunkarthik-periyaswamy]

📋 Steps followed to solve the problem

Comment: I have moved Python.md and NodeJS.md from the Howtos to Developer section. Then I have changed the redirecting url in Developers section from howtos to developers section.

[rbouqueau]

It was merged by @nlsdvl so I'm closing.