I'm looking for a website/software that would allow me to put my logo in the cool environments such as in those. Could you please recommend me anything?
You need a bitmap image editor.
A mockup is a simulation of a product. Sometimes it comes with an action that prepares some steps (like adding some transparency, some croping and some deformations) And helps to automatize some of the process.
But to tell you the truth, most of the examples above are realy easy to make, knowing a cuple of tools on eaither program.
You probably loose less time learning thoose than searching for a specific mockup that matches your idea.