[BDGR-103] Convert Desktop codebase and builds to ESM

[markspolakovs]

The longer we stay on CommonJS, the more of the ecosystem breaks around us. Electron will support it as of Electron 28, which becomes Nightly on 2023-08-31 so stable probably around November/December (see https://github.com/electron/electron/blob/main/docs/tutorial/esm-limitations.md)

_{From SyncLinear.com | BDGR-103}