Some gitignore content, graciously donated by openfe under MIT

[IAlibay]

Current gitignore is pretty much empty so I'm populating this to avoid merging stuff we don't need.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (225ec81) 56.06% compared to head (c490a13) 56.06%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #77 +/- ## ======================================= Coverage 56.06% 56.06% ======================================= Files 12 12 Lines 371 371 Branches 51 51 ======================================= Hits 208 208 Misses 160 160 Partials 3 3 ```

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