[macOS] Provide a arm64 (apple silicon) build of the Theia dmg

[spouliot]

Feature Description:

The current download [1] is an Intel-only binary. Still it runs, even if slower (Rosetta), on arm64-based Macs for most scenarios.

However if you try to install extensions, like the C# extension [2], you get errors [3] because the extension use the version of dotnet that match the executing architecture (and not in a way that Rosetta can help)

[1] https://theia-ide.org/#theiaidedownload
[2] https://open-vsx.org/extension/muhammad-sammy/csharp
[3]

OmniSharp server started with .NET 9.0.100-preview.4.24267.66
Path: /Users/poupou/.theia-ide/deployedPlugins/muhammad-sammy.csharp-2.34.12/extension/.omnisharp/1.39.11-net6.0/0mniSharp.dll
PID: 3703
[STDERR] Unhandled exception.
[STDERR] System.BadImageFormatException: An attempt was made to load a program with an incorrect format.
(0x8007000B)

This is similar to what happened before an arm64 version of VS Code was made available for the Mac developers.