[WIP] Add build target for Apple Silicon

[mikecee]

This change hopefully adds Apple Silicon build support as requested in #19.

• A new build matrix os is added. This takes "advantage" of the fact that latest macOS for x64 runners is macOS 13, where the new runners are at least macOS 14.
• The force build of x64 on any macOS runner (see package.json) has been removed. In theory, this means that electron-build will generate its artifacts based on the architecture of the runner.

@ubidefeo I understand that priority is for bug fixes etc. This PR is being raised as a starting point only (hence WIP), any feedback would be appreciated.

[CLAassistant]

All committers have signed the CLA.

[mikecee]

Closing to reset and resbumit; some automated changes were helpfully committed by Github