(Fix) Update eslint configuration for React app

[garatortiz]

Before submitting a pull request, please provide the following information:

• What is it? (leave one option)

  • Bug (Fix)

• What was the root cause of the problem originally / what feature was missing? When you do a npm run build, you get a linter error, and the web-dapp can not to compile

• How does this pull request solve it (in broad terms)? Adds eslint plugins to the web-dapp package json, updates the rules and fix some methods' declarations

• Does it close any open issues? No

• Quick checklist

  • [X] eslint shows no errors

    cd web-dapp
    eslint .

  • [X] docs were updated where necessary OR they don't need to be updated
  • [X] tests were updated where necessary OR they don't need to be updated

• Additional information