Prettify

[dgdavid]

This PR does basically four five things (related in some way):

• updates the entire codebase written during the HackWeek to have the same code style (using Prettier and Stylelint)

• adjust a bit more the rules and configuration used for that purpose

    "arrowParens": "always",
    "jsxBracketSameLine": true,
    "printWidth": 100,
    "singleQuote": true

• fixes present copyright headers

• adds missing copyright headers

• reintroduces the LICENSE.txt file

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Regarding the common code style, there are a few choices that I do not like either. But, if I understood correctly, we did not want to waste time discussing or reaching agreements about what we prefer. That's the reason why I introduced Prettier (now with a couple of rules tuning).

I also added a pre-commit hook and a combination of tools (lint-staged and precise-commits) with the intention to

ensure that the staged code is formatted consistently.

In other words, to format automatically the stated coded (precise-commit) and add the changes to the same commit (lint-staged).

That way,

after enough time has passed, our codebase will be formatted consistently

But something went wrong and this goodwill turned in small headaches (#243, #248, #249). Sorry guys! 😅

However, the hook is still there (now also fixing automatically the CSS 🙄), because I think the mentioned headaches were because a mistake in the configuration. Nevertheless, we need to discuss if we will keep the hook as it is (fixing things silently) or change it to abort the commit.

And... THAT'S ALL! 😜