ARM64 installation support, End of Support for DOpus 12

[Leo]

The installer issue in the past was that it would want to install 32-bit on ARM if given the choice of both versions, but if we only have 64-bit for the installer to worry about then it's no longer an issue (at least from our limited testing with ARM so far).

@me54899

Moreover, I would like inquire about the End of Support for DOpus 12: When will fixes for compatibility issues with Windows 11, and potential security issues, no longer be fixed?

We'll still be updating Opus 12 with security updates and similar until Opus 13 is out of beta. After that, it will depend on the type of issue.

@me54899

In "removed features", you mention "The ability to change the root of the folder tree has been removed." I get it that there seems to be some new way in which the Tree works, but may I still ask if "Desktop" is the default "root"?

The tree now has multiple roots which you can turn on and off and move around. Desktop is one of them. Some roots (e.g. This PC) have an option to show them at the top level or under Desktop.