feat: better compatibility

[Olyno]

Description

This pull request adds more compatibility with existing tools. Templates become monorepos, and now support the other popular package managers, namely yarn' and pnpm.

The .sh files are not compatible with Windows, so I changed to a "scripts" folder instead, which gathers the different "sh" scripts but in Javascript (making them compatible with Windows).

tltr:

• Move .sh scripts to a scripts folder, and change the format to JS
• Add yarn 2+ and pnpm support
• Switch template to monorepos, removing package-lock.json files

Note: I also renamed contract to contracts instead, which make more sense to me. This is something optional that i can revert if you won't*

[maxhr]

Thanks @Olyno for the contribution! We'll get to reviewing it this week. First comment - we don't want to introduce an additional prompt question to the users. Advanced users should be able to choose their package managers but newbies shouldn't be aware that there is such thing. How do you think we should solve it?

[Olyno]

Hi @maxhr! What we could do is to display the prompt only if there are other package managers detected (like yarn or pnpm). So a newbie will not see the prompt, but a more advanced developer will have the choice.

What do you think?