Transifex: Improved GitHub Integration

Are working with Transifex to enable fully seamless GitHub integration that removes the risk of translation being stuck in limbo when project maintainer forgets to download them periodically from Transifex.

### GitHub → Transifex

**Uploading** content from the designated GitHub repository to Transifex should **happen automatically upon changes on `master` branch**.
- > Right now the sync is twice a day, this change will ensure Transifex reflects `master` in realtime

### Transifex → GitHub

**Downloading** localized content from Transifex back to GitHub should be automated as well.
- > Right now it is done manually by project maintainer, but people often forget to do this manual step and new translations are stuck in limbo for weeks.
- We want to have following setup: When specific locale is 100% done, Transifex should open a Pull Request against `master` branch. (Thanks to Github notification the Maintainer won't forget to sync)

cc @ipfs/wg-gui-team