Create 1.9 release branch with milestone

[makelicious]

Part of the developers will move on to 1.9.1.
Create a release branch for 1.9 and follow conventions defined below.

https://www.figma.com/board/6pWbTiYQREtCVRfvlhKSvX/Release-process?node-id=8-532&t=L2eJiZkwt0ZFzvyf-0

This will slown down the development process a bit but we achieve the benefit of risk mitigation.

[makelicious]

Branches created