Removed unused tutorials

[MatteoRobbiati]

The following tutorials were not ready, thus they are removed with this PR:

• Variational quantum regressor;
• Re-uploading classifier.

I also changed the hero height in tutorials.js in order to fit the page with only two tutorials.

[alecandido]

I also changed the hero height in tutorials.js in order to fit the page with only two tutorials.

This should not happen manually, but you should find a way to specify that does not require you to hard-code a number. No number should be put manually just because "it fits like this" (otherwise the many screens you forget, but it will also stop working as soon as you change it).

However, I will take care of this myself later on, since I'm already planning to rewrite the whole CSS.

[MatteoRobbiati]

I also changed the hero height in tutorials.js in order to fit the page with only two tutorials.

This should not happen manually, but you should find a way to specify that does not require you to hard-code a number. No number should be put manually just because "it fits like this" (otherwise the many screens you forget, but it will also stop working as soon as you change it).

However, I will take care of this myself later on, since I'm already planning to rewrite the whole CSS.

I know, it was a super fast solution, but I had in mind to try min-height to control the hero's dimension.