Create/make some basic configuration files global for overall repo consistency

[marcosdly]

• d9e910b182b0fff53621da1edd714aac63469bb0: Merging frontend/.gitignore with ./.gitignore since all current rules are interchangeable;
• 7767c3a7cc425b6bbb0cc7a7870287913733fb82: Moving .prettierrc to project root for formatting consistency across all js and ts;
• 69b3b4e935659390a8041512a3385aa91a766f73: Creating .editorconfig for generic, formatter independent, editor independent formatting functionality.

[Luiz-Suvilao]

LGTM!