Remove InstallBuilder for the macOS build and generate directly a `.dmg`

[umbynos]

Remove Installbuilder on macOS (just distribute the DMG). The DMG has to be generated by the CI and has a bundle, a link to the app folder on which you want an app to be installed (probably /Applications) and a background image.
Some subtask are required before this can be achieved:

• Rework the HTTPS certs install: add menu options in the tray menu #735
• Create autostart file on first run of the agent #738