Release 4.2.0

[Jaifroid]

We're overdue a new release of the Browser Extension, but there are a few PRs and fixes we need to wait for.

These are the steps to complete a new release:

• [x] Fix some important but relatively simple issues if possible
  • [x] #1306
  • [x] #1320
  • [x] #1342
  • [x] Ideally wait for libzim v9.3 to be compilable to WASM
• [x] Create PR to update the changelog file
• [x] Rename all higher milestones by incrementing their names, create a new 4.3 milestone and move open issues to this new one
• [x] Draft the new release with desired tag (REMEMBER NOT TO USE "v" IN TAG NAME!!!)
• [x] Run Set-AppVersion script (or manually change in 8 files) the version number to v4.2.0, also run npm install to update package-lock.json, and commit
• [x] Final tests (some can be done on https://kiwix.github.io/kiwix-js)
  • [x] Firefox OS
  • [x] IE11
  • [x] Edge Legacy
  • [x] Chromium Extension
  • [x] Firefox Extension
  • [x] Safari on macOS
  • [x] Safari on iOS
• [x] Add release date to changelog and squash/merge PR
• [x] Publish the new release (this will create the tag and start the release workflow)
• [x] Check that dockerfile built correctly
• [x] Generate unsigned extensions (should be automatically triggered on GitHub Actions by the tag creation)
• [x] Check that the PWA version was correctly set in browser-extension.kiwix.org (should be automatically triggered by tag creation)
• [x] Upload the unsigned extensions to Stores:
  • [x] Firefox MV2 - https://addons.mozilla.org/fr/firefox/addon/kiwix-offline/
    • [x] Check that the minimum Firefox version is correct
  • [x] Chrome MV3 - https://chrome.google.com/webstore/devconsole
  • [x] Edge MV3 - https://partner.microsoft.com/en-us/dashboard/microsoftedge/
  • [x] Ubuntu touch - https://open-store.io
• [x] Prepare the source code for version 4.2.1 (changes should be made to 9 files, or use the Set-AppVersion script to update 8 files, followed by npm install to update package-lock.json.)
• [ ] When available, copy the signed extension binaries to https://download.kiwix.org/release/browsers/
  • [x] Firefox - xpi downloadable from extension page
  • [ ] Chrome - crx downloadable from extension mgmt page
  • [ ] Edge - check version is published, then use direct link for Edge-specific crx
• [x] Check that the implementation on kiwix.github.io/kiwix-js/ is synchronized automatically with main
• [ ] Publicize these new versions
• [ ] Close this issue and close the v4.2 milestone