Export a jest config

[ptbrowne]

We have different jest configs per app. It would be nice to have a shared config. We could then do our customisation there, and all our apps would benefit. For example, to be able to use @testing-library/dom 's waitFor, we need jsdom@16 and this is not the default from jest. See cozy/cozy-banks#1847 (comment) for more context.

[Crash--]

Just saw this commit (cozy/cozy-libs@9b8c654) and wanted to create the issue. But already exist.

So +1 to have a jest config for our apps