Open custom server via custom url scheme

[MartinDelille]

Fix #5391

• Make github markdown command copiable
• First draft for custom url: catch url

Pull Request Checklist

• [x] I read the contributing guide
• [x] UI change has been tested on both light and dark themes, in portrait and landscape orientations and on iPhone and iPad simulators
• [x] Accessibility has been taken into account.

• [x] Pull request is based on the develop branch

• [x] Pull request contains a changelog file in ./changelog.d
• [x] You've made a self review of your PR
• [ ] Pull request includes screenshots or videos of UI changes
• [x] Pull request includes a sign off (My commit are signed: is it fine ?)

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}