Improve HTTPS Certificates detection and installation on macOS (Safari)

[Xayton]

Many users reported that the Agent does not work on macOS using Safari. Most of the time this is because they have not installed the HTTPS Certificates for localhost (this is needed only with Safari, due to the way the browser handles connections to localhost).

The HTTPS Certificates installation should be made more robust and automatic, while keeping it optional and only done when really needed (only if using Safari, and not other browsers).

• Add a function to check if the certificates are already present and get also when they will expire
• Add a function to remove existing certificates (expired or not)
• Add a way to prompt the user for confirmation (like a dialog window)
• Add a new setting installCertificates used to save if the user want's to install them or not (true, false, missing). If missing, the user should be prompted at the first check.
• Add some logic at startup, that will prompt the user if they want to install the HTTPS Certificates, explaining it's needed if they want to use the Agent with Safari.
• Add some logic so that the check above can be scheduled once every X time, and not just at startup. This way it will work even if the user keeps the Agent running for days. This function could be used in the future for other reasons too, like an auto-update functionality.

Activities

• [ ] https://github.com/arduino/arduino-create-agent/issues/925
• [ ] https://github.com/arduino/arduino-create-agent/issues/927